function trimString (str) {
  str = this != window? this : str;
  return str.replace(/^\s+/g, '').replace(/\s+$/g, '');
}


function checkEmail()
{
	var emailold1 = document.forms[0].emailold1.value;
	var emailold2 = document.forms[0].emailold2.value;
	var emailnew1 = document.forms[0].emailnew1.value;
	var emailnew2 = document.forms[0].emailnew2.value;
	
	if(emailold1==""){alert("Please enter your old email address in the first textbox.");return;}
	if(emailold2==""){alert("Please retype your old email address in the second textbox.");return;}
	
	if(emailnew1==""){alert("Please enter your new email address in the third textbox.");return;}
	if(emailnew2==""){alert("Please retype your new email address in the fourth textbox.");return;}

	emailold1 = emailold1.toLowerCase();
	emailold2 = emailold2.toLowerCase();
	emailnew1 = emailnew1.toLowerCase();
	emailnew2 = emailnew2.toLowerCase();
	
	emailold1 = trimString(emailold1);
	emailold2 = trimString(emailold2);
	emailnew1 = trimString(emailnew1);
	emailnew2 = trimString(emailnew2);
	
	if(emailold1!=emailold2){alert("The retyped version of your OLD email address does not match.");return;}
	if(emailnew1!=emailnew2){alert("The retyped version of your NEW email address does not match.");return;}
	
	
	var pos1 = emailold1.indexOf("@");
	var pos2 = emailold1.indexOf(".",pos1);
	if((pos1>0) && (pos2>pos1+1) && (emailold1.length>pos2+1)) 
	{
		pos1 = emailnew1.indexOf("@");
		pos2 = emailnew1.indexOf(".",pos1);
		if((pos1>0) && (pos2>pos1+1) && (emailnew1.length>pos2+1)) 
		{
			document.forms[0].submit();
		}
		else
		{
			alert("The NEW email address is not a valid email address. Please enter a vaild email address.");
		}
	}
	else
	{
		alert("The OLD email address is not a valid email address. Please enter a vaild email address.");
	}
}