JavaScript Forum Validation with regular expressions

**refhat** · 07-27-2010 04:18 PM

I have a form in html that I need to validate using Javascript regular expressions.

I was validating the fields one by one and it was working fine till I tried to validate email field. Even If I remove email validation field still the form validates Name correctly, atleast.

Here is my code:

Code:

<html>
<head>
	<script type="text/javascript">
	function validate()
	{
		if(document.getElementById('name').value== "")
			{
				alert("Please Fill the Name");
				document.getElementById('name').focus();
				return false;
			}
			if(!document.getElementById('phone').value.match(/^[0-9]{10}$/));
			{
				alert("Phone No. is not valid");
				return false;
			}
			if(!document.getElementById('email').value.match(/^[a-zA-Z0-9_.-]+@[a-z0-9][a-z0-9\-]{1,64}(\.[a-z]{2,4}|[a-z]{2,3}\.[a-z]{2})$/i);
			{
				alert("Email Id is not Valid");
				return false;
			}
			
		return true;
		}
	</script>
</head>
<body>
<form name="myform" id="myform" method="get">
<table border ="1" align="center" cellpadding="0" cellspacing="0">
	<tr><td>Name</td><td><input type="text" id="name" name="name" maxlength="10"></td></tr>
	<tr><td>Phone</td><td><input type="text" id="phone" name="phone"></td></tr>
	<tr><td>Email</td><td><input type="text" id="email" name="email"></td></tr>
	<tr><td>Gender</td><td><input type="radio" name="male" id="male">Male</input><input type="radio" name="male" id="male">Female</input></td></tr>
	<tr><td>3 Boxes</td><td><input type="checkbox" name="box1" id="box1">Box 1</input><input type="checkbox" name="box2" id="box2">Box 2</input><input type="checkbox" name="box3" id="box3">Box 3</input></td></tr>
	<tr><td></td><td><input type="button" value = "Submit Form" onclick="return validate();"></td></tr>
</table>
</form>
</body>
</html>

At first the phone no. field was working correctly now it too doesn't work correctly. I am not sure what did I do wrong. can someone point me to right direction as where I am doing wrong.

Is it incorrect to match using a ! operator , if so what would be the correct way to validate this form using Regular expressions.

Thanks for the help..

**Fang** · 07-28-2010 02:37 AM

Code:

if(!/^[0-9]{10}$/.test(document.getElementById('phone').value))

Use the same test for email.

**nursa** · 07-28-2010 05:01 AM

I have a more basic question about validation - can someone give me a link to a tutorial about validating input that is only numbers and letters?

i.e. i want an input that can only be a-z/0-9.

thanks

**Fang** · 07-28-2010 05:23 AM

http://www.javascriptkit.com/javatutors/redev2.shtml

**nursa** · 07-28-2010 06:09 AM

thanks Fang - one more thing - do you have to use getElement to match the value, or can you just pass a string to the function?
e.g.

Code:

function validate(string){
 if string.value != ""{
  if string.value.match(/^[0-9a-z]/){
   alert("blah")
}}}

i've tried this but i cant get it working

**Fang** · 07-28-2010 06:21 AM

If you pass a string there is no need for value

Code:

function validated(string) {
if(string != "") {
    if(string.match(/^[0-9a-z]/)) {
        alert("blah");
        }
    }
}

Also missing brackets for if statement

**nursa** · 07-28-2010 06:25 AM

lol thanks, i thought it was something that simple

**nursa** · 07-28-2010 06:33 AM

i had to use '.value' :

Code:

function validate(str) {
  alert(str.value)
  if(str.value != "") {
    alert("null check passed")
    if(str.value.match(/[^0-9a-z]/)) {
      alert("Only A-Z and 0-9 allowed!");
    }
  }
}

you do need it, this code works

**Fang** · 07-28-2010 06:36 AM

Then you are not passing a string, but a reference.

**nursa** · 07-28-2010 07:29 AM

ok cheers

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