JavaScript Getting StartedIn this tutorial you will learn how to make a JavaScript powered web page. Show
Getting Started with JavaScriptHere, you will learn how easy it is to add interactivity to a web page using JavaScript. But, before we begin, make sure that you have some working knowledge of HTML and CSS. If you're just starting out in the world of web development, start learning from here ยป Well, let's get started with the most popular client-side scripting language. Adding JavaScript to Your Web PagesThere are typically three ways to add JavaScript to a web page:
The following sections will describe each of these procedures in detail: Embedding the JavaScript CodeYou can embed the JavaScript code directly within your web pages by placing it between the
The JavaScript code in the above example will simply prints a text message on the web page. You will learn what each of these JavaScript statements means in upcoming chapters. Note: The Calling an External JavaScript FileYou can also place your JavaScript code into a
separate file with a <script src="js/hello.js"></script> This is useful if you want the same scripts available to multiple documents. It saves you from repeating the same task over and over again, and makes your website much easier to maintain. Well, let's create a JavaScript file named "hello.js" and place the following code in it:
Now, you can call this external JavaScript file within a web page using the
Note: Usually when an external JavaScript file is downloaded for first time, it is stored in the browser's cache (just like images and style sheets), so it won't need to be downloaded multiple times from the web server that makes the web pages load more quickly. Placing the JavaScript Code InlineYou can also place JavaScript code inline by inserting it directly inside the HTML tag using the special tag attributes such as However, you should avoid placing large amount of JavaScript code inline as it clutters up your HTML with JavaScript and makes your JavaScript code difficult to maintain. Here's an example:
The above example will show you an alert message on click of the button element. Tip: You should always keep the content and structure of your web page (i.e. HTML) separate out from presentation (CSS), and behavior (JavaScript). Positioning of Script inside HTML DocumentThe Each Tip: You can place any number of Difference Between Client-side and Server-side ScriptingClient-side scripting languages such as JavaScript, VBScript, etc. are interpreted and executed by the web browser, while server-side scripting languages such as PHP, ASP, Java, Python, Ruby, etc. runs on the web server and the output sent back to the web browser in HTML format. Client-side scripting has many advantages over traditional server-side scripting approach. For example, you can use JavaScript to check if the user has entered invalid data in form fields and show notifications for input errors accordingly in real-time before submitting the form to the web-server for final data validation and further processing in order to prevent unnecessary network bandwidth usages and the exploitation of server system resources. Also, response from a server-side script is slower as compared to a client-side script, because server-side scripts are processed on the remote computer not on the user's local computer. You can learn more about server-side scripting in PHP tutorial section. What are the 3 ways you can include JavaScript in your web?Adding JavaScript to Your Web Pages. Embedding the JavaScript code between a pair of <script> and </script> tag.. Creating an external JavaScript file with the . ... . Placing the JavaScript code directly inside an HTML tag using the special tag attributes such as onclick , onmouseover , onkeypress , onload , etc.. Where do I put JavaScript script in HTML?JavaScript in body or head: Scripts can be placed inside the body or the head section of an HTML page or inside both head and body. JavaScript in head: A JavaScript function is placed inside the head section of an HTML page and the function is invoked when a button is clicked.
Can you write JavaScript in HTML?The first way to add JavaScript to HTML is a direct one. You can do so by using the <script></script> tag that should encompass all the JS code you write. JS code can be added: between the <head> tags.
How do I connect JavaScript and HTML?We can link JavaScript to HTML by adding all the JavaScript code inside the HTML file. We achieve this using the script tag which was explained earlier. We can put the <script></script> tag either inside the head of the HTML or at the end of the body.
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