Change value of input on form submit in JavaScript?

Javascript Web Development Object Oriented Programming

To change value of input, use the concept of document. The syntax is as follows −

document.yourFormName.yourTextName.value=anyValue;

Let’s say the following is our input type calling submitForm() on clicking “Submit Form” −

<form name="studentForm" onsubmit="submitForm();">
   <input type="hidden" name="txtInput" value="10000" />
   <input type="submit" value="Submit Form"/>
</form>

The submitForm() function changing the value of input −

function submitForm(){
   document.studentForm.txtInput.value='STUDENT-100';
}

Example

Live Demo

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initialscale=1.0">
<title>Document</title>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"
></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.
css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u"
crossorigin="anonymous">
</head>
<body>
<form name="studentForm" onsubmit="submitForm();">
<input type="hidden" name="txtInput" value="10000" />
<input type="submit" value="Submit Form"/>
</form>
<script>
   function submitForm(){
      document.studentForm.txtInput.value='STUDENT-100';
   }
</script>
</body>
</html>

To run the above program, save the file name “anyName.html(index.html)” and right click on the file. Select the option “Open with Live Server” in VS Code editor.

Output

This will produce the following output −

On clicking the button “Submit Form”, you will get the change value in query string. This will produce the following output −

AmitDiwan

Published on 07-Sep-2020 07:55:37

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