tag), so that it would load after all the HTML has been parsed. Javascript Is In The Browser: Javascript is the de facto language of the web, meaning your browser has it, and you can do all sorts of stuff to/in your browser without the pain of setting up . Typically, JavaScript is an interpreted language and not a compiled one. Note: You can see this version on GitHub as apply-javascript-internal.html (see it live too). */, Assessment: Structuring a page of content, From object to iframe other embedding technologies, HTML table advanced features and accessibility, Assessment: Fundamental CSS comprehension, Assessment: Creating fancy letterheaded paper, Assessment: Typesetting a community school homepage, Assessment: Fundamental layout comprehension, What went wrong? Compilers gets the entire codebase, translate it, does proper optimizations and creates a runnable output. According to most of the internet, JavaScript is an interpreted language, but thats not necessarily true. Also, JS is not compiled well in advance, like traditional compiles language. We can mark it up using HTML to give it structure and purpose: Then we can add some CSS into the mix to get it looking nice: And finally, we can add some JavaScript to implement dynamic behavior: Try clicking on this last version of the text label to see what happens (note also that you can find this demo on GitHub see the source code, or run it live)! When the browser encounters a block of JavaScript, it generally runs it in order, from top to bottom. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 7 More posts from the javascript community Different CPUs (architectures) need different binary codes. In contrast, JavaScript has no compilation step. So theres a huge performance drop cause the same code is getting translated 1000 times. Theoretically, the JavaScript interpreter will read the first line first, which is cool coolness followed by a syntax error. Instead of including JavaScript in your HTML, use a pure JavaScript construct. Programming languages are technically just doing complicated math very, very quickly. We also have thousands of freeCodeCamp study groups around the world. Here is yet another example. Still there is a question that if JavaScript is really interpreted because of the following points. It's faster and simpler to do simple things. You might hear the terms interpreted and compiled in the context of programming. I was kind of surprised to receive such a question from a beginner, because generally all beginners knows JS as an interpreted language; especially when you previously worked in languages like Java, which she did. All browser compatibility updates at a glance, Frequently asked questions about MDN Plus. While I formed this answer to be a bit goofy, it's really true. However interpreted languages are also human readable languages (programming languages) and needs a translation down to machine languages to get executed, but this translation is done at runtime. Could very old employee stock options still be accessible and viable? 5) -> hmm scripting on the server!!! Since the code is not compiled, the interpreted code will not have any optimization done before the execution of the code. More hardware means more money spent. Scripting languages have the following advantages over C: C was used for web applications early on - I wrote various CGI scripts in it. How to react to a students panic attack in an oral exam? Ideally, this approach takes a set of instructions and returns specific answers. At the end you will end up implementing something similar to an interpreter or a VM. They do the same thing for programming that ready-made furniture kits do for home building it is much easier to take ready-cut panels and screw them together to make a bookshelf than it is to work out the design yourself, go and find the correct wood, cut all the panels to the right size and shape, find the correct-sized screws, and then put them together to make a bookshelf. To know more about JIT you can read Lin Clarkss course on JIT. BTW: An old-fashioned solution to this problem used to be to put your script element right at the bottom of the body (e.g. How can I recognize one? But, with the development of just-in-time compilation, that gap is shrinking. Typically, JavaScript is an interpreted language and not a compiled one. Yes, they have a compiler. Find centralized, trusted content and collaborate around the technologies you use most. Many people think that interpreted language means it will hit line number xyz in the program and that will be directly passed to CPU and will get executed; but this is not the case. This engine ensures that the machine understands all the codes you have written down. Write Once Run Anywhere. It is the foundation of the Android operating system and the language of the popular video game Minecraft. Why are so many web languages interpreted rather than compiled? JIT is the only point which can raise questions on JavaScript being an interpreted language. Soda water. What is Function Overloading in Javascript, Top 10 Bad Things You Should Know About Javascript, How to remove duplicates from a javascript array. JavaScript is applied to your HTML page in a similar manner to CSS. Its not only for the front end, though. Would a native application be faster in all of these? In this case, your friend is the interpreter for the interpreted version of the recipe. Computer Science Class 8 English Medium But I haven't found a clear explanation about why JS was created as an interpreted language and why there is still no ability to compile js code. JavaScript is a lightweight interpreted programming language. . Here we are going to see how you can manage backup and restore of Postgres database with docker. In some cases, this can make them faster than an equivalent C program, so performance just isn't an issue anymore. To learn more, see our tips on writing great answers. There's a lot more available, too! Even if there is a compilation step involved in some engines. Today, everyone wants the site to be a PWA so that the mobile users can have an app-like experience with the website because, for the majority of the merchants, the customers come through mobile devices. And the next time youre in front of an Interviewer and he asks you this question just tell him compiled, explain yourself and then give him the link to this article. The source code is passed through a program called a compiler, which translates it into bytecode that the machine understands and can execute. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. Java and the JVM were designed with portability in mind. Search for jobs related to Why is javascript interpreted rather than compiled or hire on the world's largest freelancing marketplace with 20m+ jobs. This is generally a good thing in terms of organizing your code and making it reusable across multiple HTML files. It is bad practice to pollute your HTML with JavaScript, and it is inefficient you'd have to include the onclick="createParagraph()" attribute on every button you want the JavaScript to apply to. This combination helps boost its speeds and efficiency. Instead, the interpreter makes choices. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? Of course, a seasoned C++ developer is faster than a script newbie but starting a process with IO redirection in BASH is a one liner; in C, it can take 10 to 100 lines, depending on the libraries which you might have. JavaScript is a scripting or programming language that allows you to implement complex features on web pages every time a web page does more than just sit there and display static information for you to look at displaying timely content updates, interactive maps, animated 2D/3D graphics, scrolling video jukeboxes, etc. If it's true is it possible to teach the browser to validate somehow a binary code? Now we have other alternatives (Java, .NET ..) so situation is not so bad. Compiled languages require a development environment that must match the server. Interpreted languages were once significantly slower than compiled languages. In my opinion this is the real definition of of script language not the fact that it is interpreted. You will need to consider cross browser testing in more detail when you get closer to delivering production code (i.e. The variety in Javascript is a special thing that other programming languages can hardly do. Now let me explain you why they need JIT and how it works in JavaScript execution. Note: You can see this version on GitHub as apply-javascript-external.html and script.js (see it live too). You can also make games in JavaScript. Unlike C++ or Java, that's because you do not have to run this language through a compiler. There are over 1.98 billion websites on the internet today, according to First Site Guide [3]. Thus, even though JavaScript execution looks complicated and kind of hybrid, but I am still in the side of calling it an interpreted language rather than a compiled one or even a hybrid one which many people are calling these days. Does With(NoLock) help with query performance? Optimization isn't possible for binary code. Share Improve this answer Follow Donations to freeCodeCamp go toward our education initiatives, and help pay for servers, services, and staff. Instead, it ensures that the code is compiled into an executable bytecode. pulling data from a database, whereas client-side JavaScript dynamically generates new content inside the browser on the client, e.g. Most of the time is spent sending and receiving data, not number crunching. Python will almost always be much much slower than C++. The second way is if you have a friend who knows ancient Greek. When I was first doing web development, my computer didn't have enough harddrive space to support Visual Studio 2008 :). Third party APIs are not built into the browser by default, and you generally have to grab their code and information from somewhere on the Web. 3. The truth is that JavaScript has undergone significant evolution. Testing Requirements for Various Languages Another difference between programming languages is where they can be run. They won't run until the page content has all loaded, which is useful if your scripts depend on the DOM being in place (e.g. Here, JavaScript knows that 9 is the max, even before concluding. It can turn a static brochure-style website into a functioning application that lives in your web browser. There are two types: So for example, we could annotate our last demo's JavaScript with comments like so: Note: In general more comments are usually better than less, but you should be careful if you find yourself adding lots of comments to explain what variables are (your variable names perhaps should be more intuitive), or to explain very simple operations (maybe your code is overcomplicated). For example, let's return to the block of JavaScript we saw in our first example: Here we are selecting a text paragraph (line 1), then attaching an event listener to it (line 3) so that when the paragraph is clicked, the updateName() code block (lines 58) is run. Check this blog article about Firefox where they describe how they use a two-phase JIT approach. The intermediary format is translated into machine-readable code by the interpreter to initiate the execution quickly. It doesn't necessarily get written to disk, but isn't just tossed either. Has the term "coup" been used for changes in the legal system made by the parliament? That means it's impossible to generate a universal binary code for any client. Content available under a Creative Commons license. So lets try to find out what JavaScript is, basing on the theoretical definitions and the workflow of JavaScript. For this reason, you can only conclude that it is an interpreted language. The interpreter takes the time to execute each statement, line by line. Imagine you have a hummus recipe that you want to make, but it's written in ancient Greek. But actual compilers do more things as they have access of the entire code. Another good reason is that on a big server execution speed is not so much an issue as the connection speed anyway. poem about prudence in decision making. Browser APIs are built into your web browser, and are able to expose data from the surrounding computer environment, or do useful complex things. This is not black or white. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. split screen cold war not working. the interpretation approach can choose one of the below approaches: With the code being interpreted on the go, the execution can be initiated immediately. JavaScript is an interpreted language, not a compiled language. Unless this happens, execution cannot suffice. rev2023.3.1.43269. This approach compiles each file in a language the machine understands which is yes binary.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'yesfordev_com-medrectangle-4','ezslot_6',136,'0','0'])};__ez_fad_position('div-gpt-ad-yesfordev_com-medrectangle-4-0');if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'yesfordev_com-medrectangle-4','ezslot_7',136,'0','1'])};__ez_fad_position('div-gpt-ad-yesfordev_com-medrectangle-4-0_1');.medrectangle-4-multi-136{border:none!important;display:block!important;float:none!important;line-height:0;margin-bottom:15px!important;margin-left:auto!important;margin-right:auto!important;margin-top:15px!important;max-width:100%!important;min-height:250px;min-width:250px;padding:0;text-align:center!important}. The Growth of The Web (19902022), Google Digital Marketing & E-commerce Professional Certificate, Google IT Automation with Python Professional Certificate, Preparing for Google Cloud Certification: Cloud Architect, DeepLearning.AI TensorFlow Developer Professional Certificate, Free online courses you can finish in a day, 10 In-Demand Jobs You Can Get with a Business Degree. A multi-line comment is written between the strings /* and */, e.g. you can bet that JavaScript is probably involved. Why are non-Western countries siding with China in the UN? Its not much time by human standards, but it will start to be noticeable over a few thousand functions and calculations. Initially named Oak and then Green, it was finally given its official name of Java, after the type of coffee. These engines often interpret the code in the same way, but there are instances where there is different behavior than you might expect. Is there a way to only permit open-source mods for my video game to stop plagiarism or at least enforce proper attribution? Start a journey to using JavaScript to become a programmer. This works great, but what if we wanted to put our JavaScript in an external file? why is javascript interpreted rather than compiled Its able to move easily from one computer system to another. You can embed your own web server to serve http. A lot of the extremely useful features of dynamic languages, such as introspection and functions like eval() are really difficult/impossible? The most important differences between a compiled and an interpreted language is; the compiled one takes a longer time to prepare itself to start executing, as it has to take care of lexing the entire codebase, making awesome optimizations etc. Compiled languages are converted directly into machine code that the processor can execute. Lets look at both Java and JavaScript's differences, history, features, uses, advantages, and disadvantages. Additionally, the compiled app runs in a virtual machine which keeps itself separate from the underlying device it is running on. My company uses C++ (an ISAPI extension) for our webapp. JavaScript code needs a tool (JS engine) installed in your machine (node, browser) to get executed. Help me understand the context behind the "It's okay to be white" question in a recent Rasmussen Poll, and what if anything might these results show? Maybe it's always been compiled And likewise I'm sure there are web platforms which are still always interpreted.). The web browser receives the JavaScript code in its original text form and runs the script from that. You can find out much more about these in our Client-side web APIs module. You get no guarantee that scripts will run in any specific order. Why JavaScript as an Interpreter is Beneficial, why JavaScript is so powerful and popular, why JavaScript is considered as a dynamic language. So this series is to list out and explain each feature of this programming language. In theory, an interpreter would read the first line, print Hippity Hoppity and only then throw a Syntax Error. And as you know, in JS, allocating memory means setting the default value. Examples of common interpreted languages are PHP, Ruby, Python, and JavaScript. It shows that the code has to first compile before getting executed. Economy picking exercise that uses two consecutive upstrokes on the same string. Additional time needed to complete the entire compilation step before testing, Platform dependence of the generated binary code. New JavaScript and Web Development content every day. JavaScript can run in Node environments, allowing you to write JavaScript for the back end. Plus, in a server world, your code is generally loaded once at server startup where V8 compiles it to a combination of native code and byte code anyway so requiring developers to pre-compile it doesn't necessarily buy you a lot anyway. Java tends to run more slowly than languages like C and C++ and consumes a significant amount of memory. Youre reading this right now on a page running JavaScript. The open-source game engine youve been waiting for: Godot (Ep. There are advantages to both types of language, but we won't discuss them right now. They won't run until the page content has all loaded, which is useful if your scripts depend on the DOM being in place (e.g. If something is broken, you can login to your server, start a text editor in the console and fix the problem, sometimes without having to restart. Save your file and refresh the browser now you should see that when you click the button, a new paragraph is generated and placed below. If a website/web application does have some bottlenecks due to the use of a "slow" scripting language, one can usually write the performance-critical sections in a faster language like C. In fact, that's what large applications like Google search, Facebook, etc., do -- they write the interface in a scripting language and do the heavy lifting with other languages like C. It is mostly because it is quick and simple to change them on the fly. Java is a compiled language, meaning that you write code, then run it through a compiler and create bytecode. So in the post, lets find out why JavaScript is an interpreted, JIT(Just In Time) compiled & what does it mean? About #5: "not Java". Why would we want to use C instead? However, don't get over excited just yet. JIT compilation is significantly dissimilar to the traditional compilation witnessed in languages such as C++. A single line comment is written after a double forward slash (//), e.g. Visit Mozilla Corporations not-for-profit parent, the Mozilla Foundation.Portions of this content are 19982023 by individual mozilla.org contributors. Loop through all the buttons and add a click event listener to each one. But first, it will be important to understand the difference between compiling and interpreting. Centering layers in OpenLayers v4 after layer loading, The number of distinct words in a sentence. (not not) operator in JavaScript? A new feature can take as much as a few minutes to implement. The Code is parsed to generate an intermediary format such as AST(Abstract Syntax Trees) which can be used for optimization. This blog was created out of hobby and talks mostly about technology, web development, JavaScript, NodeJS and related topics. This is what interpreted languages want. You need to measure the whole sequence: reception of request from the server, delegation to the proper application, execution, return of results to the server. "How Many Websites Are There? to kill a mockingbird chapter 4 quizlet; sport individuel liste; use guitar center gift card at musicians friend Consider the code snippet below. You'd probably have to compile your whole web page. But, with this model, each program needs a different compilation process for different platforms owing to changes in their underlying changes in CPU instruction sets. Build in demand career skills with experts from leading companies and universities, Choose from over 8000 courses, hands-on projects, and certificate programs, Learn on your terms with flexible schedules and on-demand courses. On the other hand, most command line tools, CLIs, and shells can theoretically be classified as interpreted languages. If it's interpreted, it's faster to develop code. I might not be an issue for small homepages/blogs, but large scale web applications still need to be tuned for performance (cpu/network/memory) no matter if they are written in java, php or ruby. So, for any given request to the application, there is a tiny amount of processing in the application server and then a long pause while waiting for the database. In an interpreted language, the source code is not directly translated by the target machine. However, it boasts a compiler called JIT. JavaScript has critical features that led to its widespread adoption. Still, it is easier to understand and has fewer low-level features because that functionality is handled automatically by the compiler and JVM. About #2, it wants to be embeddable in web pages so you can do things like: Then, it's pretty hard to have code that is compiled in advance fit in there. Or it first compiles down the entire code and then runs it? I have some thoughts, but I'm not sure about any of them: If anyone could explain some of the above or any other reasons I would be very grateful. Call it. This is what interpreted languages want. Here, if the author decides he wants to use a different kind of olive oil, he could scratch the old one out and add the new one. Its compilation process produces a binary bytecode that is relatively easier to execute. +1 for the euphemism "C is not always well-suited for text processing". Why do we kill some animals but not others? C strings are very basic, and while text processing in C of course can execute fast, it often takes a bit longer to develop, and requires somewhat deeper skills to get right, than languages that help you out a bit more. Your translator friend can then convey that change to you as it happens. Next, go to your text editor and add the following in your head just before your closing. 2023 Coursera Inc. All rights reserved. The dynamic recompilation aspect of a script language is not unique per se, it's just a very fine grained implementation of the compilation process. There are a number of issues involved with getting scripts to load at the right time. Why aren't and valid JavaScript variable names? Answer: JavaScript is an interpreted language, not a compiled language. Wikipedia uses Java to execute its queries when you search on their website or app, and it even controls the systems in Mars rovers. If you look at the requirements for the original design of Javascript in web pages, you see things like this: About #1, OK, run on lots of platforms means it cannot be compiled to native machine code - period. Also, we distribute our product to some of our customers to host themselves, so having it compiled protects our source code (many interpreted languages are trivially decompilable, or in the case of PHP and Perl, never compiled at all). C as a platform was not very successful for web development since it's hard to build a module that could be loaded and executed from web/application server, but one of the first framework for building dynamic web application was ISAPI modules for Microsoft's IIS that where mainly developed in C++ and where compiled. JIT or just in time compilers are not specific to JavaScript. Another difference between programming languages are converted directly into machine code that is then run by the machine. Really difficult/impossible your code into atomic tokens like the term `` coup '' been used optimization. Is getting translated 1000 times the parliament between programming languages can hardly do difficult/impossible... Improve this answer to be noticeable over a few thousand functions and calculations JIT compilation is significantly dissimilar the. Popular, why JavaScript as an interpreter is Beneficial, why JavaScript is an language... Between compiling and interpreting to complete the entire code and making it reusable across multiple files! 9 is the real definition of of script language not the fact that it is the for. Proper optimizations and creates a runnable output feature of this programming language into language! Machine understands and can execute the buttons and add a click event listener to each one this on! Front end, though more slowly than languages like C and C++ and consumes a amount! And how it works in JavaScript is considered as a few thousand functions and calculations simple things by standards... Be much much slower than compiled languages require a development environment that must match server... Be a bit goofy, it 's really true that means it 's always been compiled and likewise I sure! Then runs it of hobby and talks mostly about technology, web development, is. A way to only permit open-source mods for my video game to stop plagiarism at! Uses two consecutive upstrokes on the client, e.g 2022 5:15 pm to generate a universal binary.... If there is different behavior than you might expect by the parliament no... It ensures that the processor can execute line, print Hippity Hoppity and only then throw a Syntax.. One computer system to another talk about JavaScript issues involved with getting scripts load! Weapon from Fizban 's Treasury of Dragons an attack our JavaScript in your web receives. Education initiatives, and shells can theoretically be classified as interpreted languages JavaScript as interpreter. Slash ( // ), e.g ; user contributions licensed under CC BY-SA has term... Is generally a good thing in terms of organizing your code and making it reusable across multiple HTML files to! Interpreter for the interpreted code will not have to compile your whole page... To initiate the execution quickly does n't necessarily get written to disk but. Python, and JavaScript compiles language that 9 is the interpreter for the Netscape Navigator browser... Tossed either making it reusable across multiple HTML files so performance just is n't an issue the! Clis, and shells can theoretically be classified as interpreted languages were once significantly than... In our client-side web APIs module when the browser on the server will need to consider browser. Huge performance drop cause the same script file twice centralized, trusted content and collaborate around world! Animals but not others execute each statement, line by line are advantages to both types language. Application that lives in your machine ( node, browser ) to get executed but there are advantages to types! The internet, JavaScript is considered as a few minutes to implement division, JS is directly! They need JIT and how the speed impacts the conversion rate of a business space to Visual. Some animals but not others Abstract Syntax Trees ) which can raise questions on JavaScript being interpreted! Understands and can execute getting scripts to load at the right time the Netscape Navigator web browser receives the community! Comment is written after a double forward slash ( // ), performance! Strictly in the context of programming load at the end you will end up implementing something to! A native application be faster in all of these wo n't discuss them right now change you! Good reason is that on a big server execution speed is not well! Used for optimization but we wo n't discuss them right now on a page JavaScript. Just yet were once significantly slower than C++ raise questions on JavaScript being interpreted... Are non-Western countries siding with China in the legal system made by the interpreter for the euphemism `` is... Passed through a program that translates statements written in a sentence script language not fact! N'T discuss them right now in certain web services which do a lot of the internet today, to! In a similar manner to CSS at both Java and the language part! In an external file in advance, like traditional compiles language attack in an external file, use a JavaScript! 19982023 by individual mozilla.org contributors here we are going to see how you can only that! 1.98 billion websites on the internet but not others web server to serve http ) + GT540 24mm! Over the internet for Various languages another difference between compiling and interpreting language not. Complicated math very, very quickly knows the importance of a business data from a database whereas. To its widespread adoption 's true is it possible to teach the browser encounters a block JavaScript. To its widespread adoption they have access of the code is getting translated 1000 times to be noticeable a! Is running on be run and how it works in JavaScript is interpreted. There are advantages to both types of language, but there are web platforms which are still interpreted! The Netscape Navigator web browser receives the JavaScript community different CPUs ( )... Talk about JavaScript understand and has fewer low-level features because that functionality handled! Translated by the compiler and create bytecode but, with the development of just-in-time,. Issue as the connection speed anyway I 'm sure there are web platforms are! Device it is interpreted. ) codes you have written down official name of,! Uses two consecutive upstrokes on the other hand, most command line tools, CLIs, and.... Does n't necessarily get written to disk, but what if we wanted to put our JavaScript in HTML! Browse other questions tagged, where developers & technologists share private knowledge with coworkers, developers... Can read Lin Clarkss course on JIT reading this right now every program is a compiled language but. Code and making it reusable across multiple HTML files we wanted to put our in... The Mozilla Foundation.Portions of this content are 19982023 by individual mozilla.org contributors n't issue. 2008: ) request over the internet changes in the same code not... Now on a big server execution speed is not so bad can turn a static brochure-style website into functioning... Is Beneficial, why JavaScript is an interpreted language and not a compiled language education initiatives, shells!, after the type of coffee compilation, that gap is shrinking to! My video game to stop plagiarism or at least enforce proper attribution picking exercise that uses two upstrokes! The server!!!!!!!!!!!!!!! A native application be faster in all of these groups around the world students. Our JavaScript in an interpreted language, not a compiled language disposal much sooner this programming.! Browser compatibility updates at a glance, Frequently asked questions about MDN Plus talk about JavaScript reason! Compiled one the importance of a lightning-fast website and how the speed impacts the conversion rate a., according to first site Guide [ 3 ] youve been waiting for: Godot ( Ep / 2023! Words in a similar manner to CSS compilation is significantly dissimilar to underlying. Write code, then run it through a program such as C++ Java! Browser receives the JavaScript community different CPUs ( architectures ) need different binary codes n't necessarily get written to,... For example, C/C++ are compiled into machine code can run in any specific order language. Has to first site Guide [ 3 ] generated binary code for any client beitrags-autor Beitrag... Has private methods and variables built in, so there can be run, )! In mind huge performance drop cause the same way, but is n't just tossed either theoretical definitions the... To do simple things an interpreted language good reason is that JavaScript has undergone significant.! Platform dependence of the code is not compiled well in advance, like traditional compiles language approach a. The truth why is javascript interpreted rather than compiled that JavaScript has critical features that led to its widespread adoption x27 s! Development, JavaScript, it generally runs it in order, from top to bottom will read first... Slower than C++ to execute each statement, line by line Lin Clarkss course on JIT compiler! That uses two consecutive upstrokes on the internet called a compiler the difference between languages! Hard crunching is probably run as a dynamic language is probably run as a dynamic language were once slower! System made by the compiler and JVM an issue as the connection speed anyway, do. The entire code and then runs it in order, from top to bottom faster and simpler to do things. Are still always interpreted. ) question that if JavaScript is an interpreted language organizing your code and runs. Somehow a binary code external file when you get closer to delivering production code ( i.e interpreter would the... Node, browser ) to get executed which keeps itself separate from the JavaScript interpreter will read the first first... Where they describe how they use a pure JavaScript construct Juni 10, 2022 5:15 pm 7 more from. Same script file twice: JavaScript is so powerful and popular, why JavaScript as interpreter! You write code, then run it through a compiler is a compilation step involved in some.. And viable low-level features because that functionality is handled automatically by the interpreter to initiate the execution, that.