问如何使用mysql DB、PHP和jQuery动态地进行可靠的选择

EN

<script>
    function updateCitiesSelectOptions(state) {
    // Perform a request to your php an return in your case the html
    // is also common to return just an array with the elements 
    // and print the html with javascript

        // https://api.jquery.com/jQuery.get/
        $.get( '/path/to/script/returning/the/html', { state: state }
        .done(function( data ) {
            // here the cities selector is updated
            $("#cities").html(data);
        });
    }

    function updateBanksSelectOptions(city) {
        $.get( '/path/to/script/returning/the/html', { city: city }
        .done(function( data ) {
            // here the banks selector is updated
            $("#banks").html(data);
        });
    }

    // Bind the functions to the change events of the selectors.
    $("#state").bind("change",function(){
        updateCitiesSelectOptions($(this).val());
    });

    $("#cities").bind("change",function(){
        // If you need the state for the query send it here also
        updateBanksSelectOptions($(this).val());
    });
</script>

<?php
    // You will receive the state and the city in $_GET variable as we are performing a
    // $.get javascript call

    // Escape the input preventing MySQL injections
    // Note that the method is deprecated and consider to update your database access
    // http://php.net/manual/es/function.mysql-real-escape-string.php  
    $state = mysql_real_escape_string($_GET["state"]);
    $result = db_query("select * from table where state = $state");
    while ($node = db_fetch_object($result)) {
        echo "<option value='$node->slug'>$node->name</option>\n";
    }
?>

// You will need different scripts to return the html or only one being parameterized. 

// i.e. 
// Data sent via javascript
{ action: "cities", state: state }

// Data sent via javascript
{ action: "banks", cities: state }

<?php 
    if ($_GET['action'] == "cities") 
        // Return cities <options> 
    if ($_GET['action'] == "banks") 
        // Return bank <options> 
?>