String length validation in JavaScript is used to make sure that the number of characters entered in a specified field will be restricted. For example, the name field should have a length of 8-10 characters only.
Example:
<!DOCTYPE html>
<html lang="en">
<head>
<script>
function stringLengthCheck(name, minlength, maxlength)
{
var mnlen = minlength;
var mxlen = maxlength;
if(name.value.length<mnlen || name.value.length> mxlen)
{
alert("Name should be " +mnlen+ " to " +mxlen+ " characters.");
return false;
}
else
{
return true;
}
}
</script>
</head>
<body>
<div class="mail">
<h2>JavaScript String Length Validation</h2>
<form name="form1" action="#">
Name: <input type='text' name='name'/></br></br>
<input type="submit" name="submit" value="Submit"
onclick="stringLengthCheck(document.form1.name, 8, 10)"/>
</form>
</div>
</body>
</html>