Javascripting Validation

var filter = /^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
    var email=$('#email').val();
    var password=$('#password').val();
    var cid='<?php echo $clid ?>';


        if ($.trim(email).length == 0) {
            alert('Please enter valid email address');
            e.preventDefault();
        }
        if (!filter.test(email)) {
            alert('Email is invalid try another!');        
            e.preventDefault();
        }
        if ($.trim(password).length == 0) {
            alert('Please enter password');
            e.preventDefault();
        }




SELECT AT LEAST ONE CHECKBOX

var checkFound = false;
for (var counter=0; counter < frmthis.length; counter++) {
  if ((frmthis.elements[counter].checked == true)) {
 checkFound = true;
 }
  }
if (checkFound != true) {
  alert ("Please check at least one checkbox.");
  return false;
  }


REGEX VALIDATION
------------------------------------------------------------------------------------------------------

http://ntt.cc/2008/05/10/over-10-useful-javascript-regular-expression-functions-to-improve-your-web-applications-efficiency.html

------------------------------------------------------------------------------------------------------
FCKEDITOR VALIDATION


var location1 = FCKeditorAPI.GetInstance('desc1');    //DESC1  iS ID OF FCKEDITOR
var contents = location1.GetXHTML(true);
 if(contents == "")
{
alert('Enter Description');
location1.Focus();
return false;
}

-------------------------------------------------------------------------------------------------------

IMAGE VALIDATION
<script>
if(document.getElementById('fakefilepc').value == "")
    {
        alert('Image  Is Required');   
        return false;
    }
    else if(document.getElementById('fakefilepc') != "")

    {
        var fup = document.getElementById('fakefilepc');
        var fileName = fup.value;
        var ext = fileName.substring(fileName.lastIndexOf('.') + 1);
        ext=ext.toLowerCase();
        var flag=0;
        var extensions = new Array("jpg","jpeg","gif","png","bmp");
        for (i = 0; i < extensions.length; i++)
        {
            if(extensions[i] == ext)
            {
                flag=1;
            }
        }
        if(flag==0)    {
            alert("This File extension not valid. Please upload valid extension image");
            return false;
        }
    }
<script>

___________________________________________________________________________________

OTHER VALIDATION

function validation()
{
var username = document.getElementById('username');
var email = document.getElementById('email');
var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
var url = document.getElementById("website").value;
//var pattern = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/;
var pattern = /http:\/\/[A-Za-z0-9\.-]{3,}\.[A-Za-z]{3}/;
// var pattern = /^(([\w]+:)?\/\/)?(([\d\w]|%[a-fA-f\d]{2,2})+(:([\d\w]|%[a-fA-f\d]{2,2})+)?@)?([\d\w][-\d\w]{0,253}[\d\w]\.)+[\w]{2,4}(:[\d]+)?(\/([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)*(\?(&?([-+_~.\d\w]|%[a-fA-f\d]{2,2})=?)*)?(#([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)?$/;
if(document.getElementById('username').value=="")
{
alert('Please enter username');
document.getElementById('username').focus();
return false;

}
else if (!filter.test(username.value))
{
alert('Please provide a valid email address')
document.getElementById('username').value="";
document.getElementById('username').focus();
return false;

}
else if(document.getElementById('password').value=="")
{
alert('Please enter password');
document.getElementById('password').focus();
return false;

}
else if(document.getElementById('password').value!="")
{
var password=document.getElementById('password').value;
if(password.length < 6)
{
alert('Please enter password more than 6 character');
document.getElementById('password').focus();
return false;
}
}
if(document.getElementById('name').value=="")
{
alert('Please enter dealer name');
document.getElementById('name').focus();
return false;

}
else if(document.getElementById('address').value=="")
{
alert('Please enter dealer address');
document.getElementById('address').focus();
return false;

}
else if(document.getElementById('website').value!="")
{
if (!pattern.test(url)) {
alert("Url is not valid");
document.getElementById('website').focus();
return false;
}
}
else if(document.getElementById('phone').value=="")
{
alert('Please enter phone number');
document.getElementById('phone').focus();
return false;

}
}
</script>