// JavaScript Document
function checkvalid(th)
	{
		if(th.firstName.value == "" || th.firstName.value == "FIRST NAME")
		{
			alert("Please enter first name.");
			th.firstName.focus();
			return false;
		}
		if(th.lastName.value == "" || th.lastName.value == "LAST NAME")
		{
			alert("Please enter last name.");
			th.lastName.value = "";
			th.lastName.focus();
			return false;
		}
		if(th.email.value == "" || th.email.value == "EMAIL")
		{
			alert("Please enter email.");
			th.email.value = "";
			th.email.focus();
			return false;
		}
		if (!(isEmail(th.email.value)))
		{
			alert("Please enter valid email address.");
			th.email.focus();
			return false;
		}
	}
function isEmail(str) 
	{
	  // are regular expressions supported?
	  var supported = 0;
	  if (window.RegExp) {
		var tempStr = "a";
		var tempReg = new RegExp(tempStr);
		if (tempReg.test(tempStr)) supported = 1;
	  }
	  if (!supported) 
		return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
		  var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
		  var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
		  return (!r1.test(str) && r2.test(str));
	}