// JavaScript Document

function check_email(str) {
		var at="@";
		var dot=".";
		var lat=str.indexOf(at);
		var lstr=str.length;
		var ldot=str.indexOf(dot);
		if (str.indexOf(at)==-1){
		    alert("Please enter a valid E-mail address");
		   return false;
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		    alert("Please enter a valid E-mail address");
		   return false;
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Please enter a valid E-mail address");
		    return false;
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Please enter a valid E-mail address");
		    return false;
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Please enter a valid E-mail address");
		    return false;
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Please enter a valid E-mail address");
		    return false;
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Please enter a valid E-mail address");
		    return false;
		 }
  	     return true;
	}


function validate_required(field,alerttxt)
{
	with (field)
	{
	if (value==null||value=="")
  		{alert(alerttxt);return false;}
		else {return true}
	}
}

function validate_form(thisform)
{
	with (thisform)
	{
		if (validate_required(user_name,"Your name is required.")==false)
		{user_name.focus();return false;} 
		
		if (check_email(user_email.value)==false)
		{user_email.focus();return false;} 
		
		if (validate_required(friend_name,"Your friends name is required.")==false)
		{friend_name.focus();return false;} 
		
		if(check_email(friend_email.value)==false)
		{friend_email.focus();return false;}
	}
	return true;
}