var request;
function validemail(evalue)
{   
if(document.frmsignup.txtemail.value=="")	
{
  alert("Please Enter The Email Address...");
  document.frmsignup.txtemail.focus();
  return false;	
}
else if(document.frmsignup.txtemail.value!="")
{
     var regExp  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
        if (!(regExp.test(document.getElementById("txtemail").value)))
        {
		   alert("Email Address is not in correct format...");
		   document.frmsignup.txtemail.focus();
            return false;
         }
	    else
		{
		   request=checkbrowser();
			if(request==null)
			{
				alert("please check Your Browser");
				return;
			}
		
		   url="chkemail.php?em="+evalue+"&mth="+Math.random();
		   request.onreadystatechange=checkemail;	
		  request.open("GET",url,true);
		  request.send(null);
		
		}
}

function checkemail()
{
var echeck;
if(request.readyState==4)
	{
		var resp=request.responseText;
		if(resp==0)
		{
		document.getElementById('emaildiv').innerHTML="This Email already exists,Choose another";
		document.getElementById('txtemail').value="";
	    document.getElementById('txtemail').focus();			
		}
		else if(resp==1)
		{
		document.getElementById('emaildiv').innerHTML="This Email is available";
		}
 	
	}	
}


// function for checking the browser compatibility of the code
function checkbrowser()
{
var request;

try
{
request=new XMLHttpRequest();
}
catch (e)
  {
	   try
		{
		request=new ActiveXObject("Msxml2.XMLHTTP");
		}
	  catch (e)
		{
			try
			  {
			  request=new ActiveXObject("Microsoft.XMLHTTP");
			  }
			catch (e)
				  {
				  alert("Your browser does not support AJAX!");
				  return false;
				  }
		}
  }
  return request;
}
}