Form validation using the javascript

In today’s post i will explain to how to validate a form using javasrcipt. This is very easy & simple javasrcipt code to validate text box. JavaScript can be used to validate data in HTML forms before sending the data to web server.

Below function check if form text box is blank .If the text box is left blank, an alerts message is display as popup on the web pages, and function returns false, and the form will not be submitted:

Javascript Code

function validateForm()
{
var x=document.getElementById("name").value;
if (x==null || x=="")
  {
  alert("Please enter the name.");
  return false;
  }
}

function validateForm()

{

var x=document.getElementById("name").value;

if (x==null || x=="")

{

alert("Please enter the name.");

return false;

}

HTML Code

Add below HTML code after body tag. In the below i have added a javascript function validateForm() and define the same function in above javascript code which will get the text box value and validate according to define rules.

<form name="contact" action="demo.php" onsubmit="return validateForm()"
 method="post">
First name: <input type="text" id="name" name="name">
<input type="submit" name="submit" value="Submit">
</form>

<form name="contact" action="demo.php" onsubmit="return validateForm()"

method="post">

First name: <input type="text" id="name" name="name">

</form>

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Form validation using the javascript

Javascript Code

HTML Code

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