Javascript PHP同步问题

Question

I want to call a javascript function with parametars that are stored in MySQL. All this is happening on an onClick event.

Here is the javascript code:

    function getFile() {
  if (window.XMLHttpRequest) {              
    AJAX=new XMLHttpRequest();              
  } else {                                  
    AJAX=new ActiveXObject("Microsoft.XMLHTTP");
  }
  if (AJAX) {
     AJAX.open("POST", "gmap.php", false);                             
     AJAX.send("searchField=" + searchField.value);
     return load(AJAX.responseText);   

  } else {
     return false;
  }                                             
}

So, the gmap.php is echoing the parameters for the javascript load function. But it doesn't load the parameter because the function is called before the MySQL query in gmap.php is executed. I've tried sync and async AJAX. If I try to call the javascript function from PHP, it doesn't get executed, because it is called on a onClick event, and this is inside a div. Please help me, I'm doing this over a week now. I've tried everything.

Here is the php code with the MySQL query:

<?php
header( 'Content-Type: text/html; charset=UTF-8' );
mb_internal_encoding( 'UTF-8' );
$a = $_POST['searchField'];
$dbhost = "localhost";
$dbuser = "*******";
$dbpass = "*******";
$dbname = "citydb";



    //connect sql
mysql_connect($dbhost, $dbuser, $dbpass);

    //select db
mysql_select_db($dbname) or die(mysql_error());
    //retrieve data
//$city=$_GET['city'];
    //escape user input to help prevent SQL injection
//$city=mysql_real_escape_string($city);
    //query
mysql_query('SET CHARACTER SET utf8');
$result=mysql_query("SELECT citystart, cityend FROM cityids WHERE city='$a' ");
if(!result) {

    die("Database query failed: " . myql_error());
    }

while($row=mysql_fetch_array($result)) {


    $lat=$row['citystart'];
    $lng=$row['cityend'];


}


    echo $lat;
    echo ", ";
    echo $lng;



?>

Answer 1

pass the php url together with the variable to search.

if (AJAX) {
     var url = "gmap.php?searchField="+ searchField.value;
     AJAX.open("POST", "url", false);                             
     AJAX.send(true);
     return load(AJAX.responseText);   
}