Cant make setTimeout() AJAX work in my PHP

Hello there. I am sooo despared since I cant make this work here is what I have in my logged_in.php file .

<html>
    <?php  echo "Welcome: "."<b>".$_SESSION["username"]."<b/>";  ?>
    <head>    
        <div id="ajax"></div>
       
                            <script type="text/javascript">
                      
                        function createXMLHttpRequest(){
                            var XMLHttpRequestObject=false;
                        
                        if(window.XMLHttpRequest)
                        {
                                       
                                      XMLHttpRequestObject=new XMLHttpRequest();
                                       return XMLHttpRequestObject;
                                 
                        } // 
                        else{
                                    if(window.ActiveXObject)
                                    {
                                    XMLHttpRequestObject=ActiveXObject("Microsoft.XMLHTTP");
                                    return XMLHttpRequestObject;
                                    }else{
                                       return false;
                                    }// End "else"  statement

                            } // End of the last "else"  statement
                        
                      }   //  End "createXMLHttpObject()" function
                      
                      HttpObject=createXMLHttpRequest();
                      //-----------------------------------------------------------------
                      function insertMessages(){
                      HttpObject.onreadystatechange=function(){
                          if(HttpObject.readyState==4 && HttpObject.status==200){
                              
                                   document.getElementById("ajax").innerHTML="";
                                    document.getElementById("ajax").innerHTML+=HttpObject.responseText;

                                  }


                              }

                                        HttpObject.open("GET","ajax_response.php",true);
                                        HttpObject.send();
                           
                      } // End  "insertMessages()" function
                     // insertMessages();
                      setTimeout("insertMessages()",1000);
                      // The below is the original "insertData()" function
                      // ------------------------------------------------------------------------
                      function insertData(user,time,message){
                      HttpObject.onreadystatechange=function(){
                          if(HttpObject.readyState==4 && HttpObject.status==200){
                              
                             // document.getElementById("ajax").innerHTML=HttpObject.responseText;
                             // document.getElementById("textarea").value+=HttpObject.responseText;
                             document.getElementById("textarea").value="";
                                    document.getElementById("textarea").value+=HttpObject.responseText;

                              
                          }
                          
                          
                      }
                    
                                HttpObject.open("GET","ajax_response.php?user="+user+"&time="+time+"&message="+message,true);
                                HttpObject.send();
                                   document.getElementById("text").value="";
                      } // End  "insertData()" function
               
                  // ------------------------------------------------------------------------
                    </script> <!--  End  The first script tag for  Ajax related functions  -->
                    
                    
        <script>
            var SESSION="<?php echo $_SESSION["username"]; ?>";
          function currentTime(){
              
           var date=new Date();
           var hours=date.getHours();
           var minutes=date.getMinutes();
           var seconds=date.getSeconds();
           var fullTime=hours+":"+minutes+":"+seconds;
            
            return fullTime;

              
          } // End "currentTime()"
            function addText(){
              
                document.getElementById("textarea").value+=SESSION+"  "+currentTime()+'\
';
                document.getElementById("textarea").value+=document.getElementById("text").value+'\
';     
            }
            
            function send(){
                if(document.getElementById("text").value!=""){
                addText();
                insertData(SESSION,currentTime(),document.getElementById("text").value);
            }
            } //  End "send()"  function
            
            
           
            
        </script>

                               

            
                    <style> #textarea { background-color:#F3F3F3;}</style>
            
        
        
    </head>
    <body>

    
        <TEXTAREA id="textarea" COLS="80" ROWS="20"   ></TEXTAREA><br/><br/>
        <input type="text" id="text" name="text"   size="96"> 
        <input type="button" value="Send" name="submit"  onclick="send()"> 
       

    </body>
</html>

And the request as I hope you saw is gonna go to ajax_response.php file . ANd inside that file I have

    <?php

                  //   PHP  Configuration
    defined("DB_HOST") ?      null: define("DB_HOST","localhost");
    defined("DB_USER")   ?    null: define("DB_USER","root");
    defined("DB_PASS")   ?    null: define("DB_PASS","");
    defined("DB_NAME")   ?    null: define("DB_NAME","livechat");

    // 1 . Creating the connection
      $connection=mysql_connect(DB_HOST,DB_USER,DB_PASS);
      if(!$connection){
          die("Couldnt create a database connection".  mysql_error());

      }// End "if"  for  creating connection
      // 2. Selecting  a database
      $selected_db=mysql_select_db(DB_NAME,$connection);
      if(!$selected_db){
          die("Could not select the database:".mysql_error());


      }//  End "if"   for selecting a database
      // 3. Perform query to the selected database
      if(isset($_GET["user"]) && isset($_GET["time"]) && isset($_GET["message"])){ //checking to see if the all $_GET variables have been set 
          $user=$_GET["user"];
          $time=$_GET["time"];
          $message=$_GET["message"];
    $query="INSERT INTO chat(user,time,message) VALUES('{$user}','{$time}','{$message}')";
    $result=mysql_query($query,$connection);
    $query="SELECT*FROM chat";
    // 4. Handling with the returned data
    $mysql_all_table=mysql_query($query,$connection);
    $row_number=mysql_num_rows($mysql_all_table);
      
    if($row_number>10){
  
                  //  Things for "ten_counter"
         $query="SELECT*FROM ten_counter WHERE id=1";
          $result=mysql_query($query,$connection);
          $fetched=mysql_fetch_array($result);
         $ten_counter=$fetched["ten_counter"];// 1
    
        // End things for "ten_counter"
        
        $ids_to_delete=10*$ten_counter;
        $query="DELETE FROM chat WHERE id<'{$ids_to_delete}'";
        $deleted_rows=mysql_query($query,$connection);
        if(!$deleted_rows){ die("Couldnt perform the query".mysql_error());}
  
                   $ten_counter++;
    mysql_query("UPDATE ten_counter SET ten_counter='{$ten_counter}' WHERE id=1");
      
    }// Delete 10 rows
       } //  End the "if"  for checking to see if the all $_GET variables have been set 
   function loadMessages(){
        $query="SELECT*FROM chat ORDER BY id ASC";
        $result=mysql_query($query);
        if(!$result){
            die("Query FAILED!!!".mysql_error());
        }
       $chat=array();
       while($row=mysql_fetch_array($result)){
        //array_push($chat,$row["user"]." ".$row["time"]."\
".$row["message"]." "."\
");
       echo $row["user"]." ".$row["time"]."\
".$row["message"]." "."\
";
           
       }
  
    }//   End  "loadMessages()" function
    loadMessages();
        

    //  5. Closing the connection
    mysql_close($connection);


    ?>

My question is why setTimeout(“insertMessages()”,1000); doesnt work : Iexpect it every 1 second go to the database take all the rows and come and output in my text area so that people that are chatting will get the answers instantly… I hope you understood my question …
And please I really need your help … Deeply appreciate your time spent on this .

For starters, with a 1 sec interval between ajax requests, you are most probably sending another ajax request before the previous one has completed. 1 second is not a lot of time for a round trip to the server and back and retrieving database records on route.