function checknull(value)
{
	
	if(value == "")
		return false;
	else
		return true;
}
function charcheck(value)
{
	flag=0;
		for(i=0;i< value.length;i++)
		
		{
		if ((value.charAt(i) >= "a" &&  value.charAt(i) <= "z")||(value.charAt(i) >= "A" && 	value.charAt(i) <= "Z")||(value.charAt(i) == " ") )
		{
			
			continue;
		}
		else

			
			return false;	



	
		}		
}

function checkalphanumeric(value)
{
	
		flag=0;
		for(i=0;i< value.length;i++)
		
		{		
		if((value.charAt(i)>="a" && value.charAt(i)<="z")||(value.charAt(i)>="A" && value.charAt(i)<="Z")||(value.charAt(i) >="0" && value.charAt(i) <="9"))
		{
			
			continue;
		}
		else

			
			return false;	


		}	

}



function emailCheck (value) {


var checkTLD=1;
var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
var emailPat=/^(.+)@(.+)$/;
var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
var validChars="\[^\\s" + specialChars + "\]";
var quotedUser="(\"[^\"]*\")";
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
var atom=validChars + '+';
var word="(" + atom + "|" + quotedUser + ")";
var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
var matchArray=value.match(emailPat);

if (matchArray==null)

{
	alert("Email Address Seems incorrect (Check @ And .'s)");
	return false;	
}

var user=matchArray[1];
var domain=matchArray[2];

for (i=0; i<user.length; i++)

{
	if (user.charCodeAt(i)>127)
	{
		alert("Ths Username Contains Invalid Characters.");
		return false;
	}
}

for (i=0; i<domain.length; i++)
{
	if (domain.charCodeAt(i)>127)
	{
		alert("Ths Domain Name Contains Invalid Characters.");
		return false;
   	}
}


if (user.match(userPat)==null)
{
	alert("The Username Doesn't Seem To Be Valid.");
	return false;
}


var IPArray=domain.match(ipDomainPat);
if (IPArray!=null) {

for (var i=1;i<=4;i++)
{
	if (IPArray[i]>255)
	{
		alert("Destination IP address is invalid!");
		return false;
   	}
}
return true;
}


 
var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;

for (i=0;i<len;i++)
{
	if (domArr[i].search(atomPat)==-1)
	{
		alert("The Domain Name Does Not Seem To Be Valid.");
		return false;
   	}
}


if (checkTLD && domArr[domArr.length-1].length!=2 && domArr[domArr.length-1].search(knownDomsPat)==-1)
{
	alert("The Address Must End In A Well-Known Domain Or Two Letter " + "Country.");
	return false;
}



if (len<2)
{
	alert("This Address Is Missing A Hostname!");
	return false;
}


return true;
}