验证邮件格式

function isEmail(theStr)
	{
		var unchar="/\\;:,";
		var atIndex = theStr.indexOf('@');
		var dotIndex = theStr.indexOf('.', atIndex);
		var flag = true;
		for (i=0;i<theStr.length;i++){	
			if (unchar.indexOf(theStr.substr(i,1)) > -1){
				return false;		
			}
		}
		theSub = theStr.substring(0, dotIndex+1)
		if ((atIndex < 1)||(atIndex != theStr.lastIndexOf('@'))||(dotIndex < atIndex + 2)||(theStr.length <= theSub.length)) 
		{	flag = false; }
		else { flag = true; }
		return(flag);
	}