function send(message){//Send message
	if(message&&message!='\n'){//If there is a message
		$.post('send.php','m='+message+'&t='+topic,processSend);//Request post.php
	}
}
 
function processSend(data){//When send.php returns
	if(data!=1){//send.php returns 1 on success
		$('#send_error').html(data).slideDown();//Give error on failure
		setTimeout("$('#send_error').slideUp();",4000)
	}
}
 
function receive(){//Recieve new messages
	$.getJSON('receive.php','p='+prev+'&t='+topic,processReceive);//Request receive.php (p=the previous message user received)
}
 
function processReceive(data){//When receive.php returns
	if(data){//If there were new messages found
		$.each(data,function(message,messageInfo){
			//Basically just adds the messages to the page and set prev as previous message
		});
	}
	setTimeout("receive()",100);//receive() again in 0.1 seconds
}

$message=trim($_POST[m]);//Get message posted
$topic=$_POST[t];//Get topic posted
if($message&&$topic){
	$message=htmlspecialchars($message);//Remove HTML
	include "../inc/global.php";//This file connects to database (below)
	$sender=$_SESSION[username];
	if($sender){//If user is logged in
		$time=time();
		mysql_query("INSERT INTO messages(topic,sender,message,time) VALUES('$topic','$sender','$message','$time')")or die(mysql_error());//Insert message into database
		echo 1;//Success
	} else{
		echo 'error';
	}
} else{
	echo 'error';
}

include "../inc/global.php";//Connects to database (shown below)
$prev=$_GET[k];//Get ID of previous message received
$topic=$_GET[t];//Get topic
 
if($prev&&$topic){	
	for($x=0;$x<10&&$newMessagesQuery=mysql_query("SELECT * FROM messages WHERE id>'$prev' AND topic='$topic'");$x++){//Loop no more than 10 times, each time setting $newMessagesQuery as a query for new messages
		if(mysql_num_rows($newMessagesQuery)){//If message(s) were found
			$nMs=array();//New Messages
			while($message=mysql_fetch_assoc($newMessagesQuery)){//Write JSON for each message
				$nMs['m'.$message['id']]['id']=$message['id'];
				$nMs['m'.$message['id']]['sender']=$message['sender'];
				$nMs['m'.$message['id']]['message']=$message['message'];
				$nMs['m'.$message['id']]['time']=$message['time'];
			}
			echo json_encode($nMs);//Output JSON
			break;//Stop loop
		} else{
			sleep(1);//If no new messages were found then sleep for 1 second and check again...
		}
	}
	if($x==10){
		echo 0;
	}
} else{
	echo 0;
}

$connection=mysql_pconnect("mywebhost.com","avario","******") or die("Could not connect to server.");//Connect to database
mysql_select_db("instantmessenger",$connection) or die("Could not locate database");
session_start();//Start Session