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How to write javascript code in jsp

PHPz

Release： 2023-04-21 09:17:19

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JSP (Java Server Pages) is a dynamic web page technology that allows Java code to be embedded into HTML to generate dynamic web page content. JavaScript is a scripting language used to interact with users. When the two are used together, various interactive effects can be created on web pages, such as form validation, dynamically changing page content, etc. In this article, we will cover how to write JavaScript code in JSP.

Step one: Introduce JavaScript files into the JSP page

In the JSP page, you can use the <script> tag to introduce JavaScript files. Set the src attribute in the <script> tag, passing the path to the JavaScript file to the attribute like this:

<html>
  <head>
    <title>My JSP Page</title>
    <script src="path/to/javascript/file.js"></script>
  </head>
  <body>
    <h1>Hello, World!</h1>
  </body>
</html>

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In the above code, We pass the path to the JavaScript file to the src attribute. The browser will automatically load the file and execute the JavaScript code in the page.

Step 2: Write JavaScript code in the JSP page

You can write JavaScript code in the JSP page, and these codes can be embedded in the <script> tag or HTML in the label. The following example demonstrates how to use JavaScript in a JSP page to change the text on the page:

<html>
  <head>
    <title>My JSP Page</title>
    <script>
      function changeText() {
        var heading = document.getElementById("myHeading");
        heading.innerHTML = "Hello, World!";
      }
    </script>
  </head>
  <body>
    <h1 id="myHeading">JavaScript Example</h1>
    <button onclick="changeText()">Click me</button>
  </body>
</html>

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In the above code, we have defined a JavaScript function called changeText(), This function can be called when the button is clicked. The function uses the document.getElementById() method to get an element on the web page, and uses the innerHTML attribute to change the text content of the element.

Step 3: Embed JavaScript code into JSP code

Sometimes, we need to embed JavaScript code into Java code in JSP code. To do this, you can use the JSP tag <% %> or <%= %> as shown below:

<html>
  <head>
    <title>My JSP Page</title>
    <script>
      <% int a = 5; %>
      var b = <%= a + 2 %>;
      console.log(b);
    </script>
  </head>
  <body>
    <h1>JavaScript Example</h1>
  </body>
</html>

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In the above code , we embed Java code in the <script> tag, and use the <%= %> tag to insert Java expressions into the JavaScript code. Console.log()The method records the value of the variable in the developer tools console.

Conclusion:

Writing JavaScript code in a JSP file is very simple. All you need to do is bring in a JavaScript file and embed the JavaScript code into a JSP tag or HTML tag. If you need to embed JavaScript code into Java code, use the JSP tag <% %> or <%= %>. By mastering these techniques, you can easily create dynamic, interactive web applications.

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