function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    return false
		 }

 		 return true					
	}

function OSValidate(){
	var your_email = document.getElementById('your_mail');
	var friend_email = document.getElementById('friend_mail');
	var err_msg = '';
	
	if (document.getElementById('name').value == '')
		{
		err_msg += 'Please enter your name.\r\n';	
		}
	
	if ((echeck(your_email.value)==false) || (your_email.value == '')){
		err_msg += "Please enter your Email.\r\n";
	}

	if ((echeck(friend_email.value)==false) || (friend_email.value == '')){
		err_msg += "Please enter your friend's Email.\r\n";
	}
	
	
	
	if (err_msg != '')
		{
			alert(err_msg);
			return false;
		}
	else
		{
		return true;	
		}
	
	
 }



 
function OSShowHide()
		{
		if (document.getElementById('float_form').style.visibility == 'visible')
			{
			document.getElementById('float_form').style.visibility = 'hidden';
			}
		else
			{
			document.getElementById('float_form').style.visibility = 'visible';
			}
		}