使用JQuery自动完成强制选择

Question

I know this question has been asked before, but I wasn't able to find any answers that are up to date or functional (at least for my application).

My JQuery autocomplete box is using a mysql database as its source. I want the user to be able to type to get recommendations, but then is forced to select from the dropdown choices before they can submit the form.

My Javascript:

    <script type="text/javascript">
    $.widget( 'ui.autocomplete', $.ui.autocomplete, {
        _renderMenu: function( ul, items ) {
            var that = this;
            $.ui.autocomplete.currentItems = items;
            $.each( items, function( index, item ) {
                that._renderItemData( ul, item );
            });
        }        
    });
    $.ui.autocomplete.currentItems = [];

    $(function() {

        $("#college").autocomplete({
            source: "search.php",
            minLength: 5
        });
    });

    var inputs = {college: false};

    $('#college').change(function(){
        var id = this.id;
        inputs[id] = false;

        var length = $.ui.autocomplete.currentItems.length;
        for(var i=0; i<length; i++){
            if($(this).val() == $.ui.autocomplete.currentItems[i].value){
                inputs[id] = true;
            }
        }
    });

    $('#submit').click(function(){
        for(input in inputs){
            if(inputs.hasOwnProperty(input) && inputs[input] == false){
                alert('incorrect');
                return false;
            }
        }
        alert('correct');
        $('#college_select_form').submit();
    });
    </script>

My form:

<form action="choose.php"  method="post" id="college_select_form" name="college_select_form">
                                        <input type="text" id="college"  name="college" class="entry_field" value="Type your school" onclick="this.value='';" onfocus="this.select()" onblur="this.value=!this.value?'Type your school':this.value;" /><input type="submit" id="submit" name="submit" class="submitButton" value="Go" title="Click to select school" />
                                    </form>

Search.php:

<?php

try {
  $conn = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
}
catch(PDOException $e) {
    echo $e->getMessage();
}

$return_arr = array();

if ($conn)
{
    $ac_term = "%".$_GET['term']."%";
    $query = "SELECT * FROM college_list where name like :term";
    $result = $conn->prepare($query);
    $result->bindValue(":term",$ac_term);
    $result->execute();

    /* Retrieve and store in array the results of the query.*/
    while ($row = $result->fetch(PDO::FETCH_ASSOC)) {
        array_push($return_arr, array('label' => $row['name'], 'value' => $row['name']));
    }


}
/* Free connection resources. */
//$conn = null; 
/* Toss back results as json encoded array. */
echo json_encode($return_arr);

?>

So what would be the best approach to doing this? The only solution I can think of is using PHP to verify that the textbox's value matches a value in the database, but I'm not sure how to implement that with my current code.

Answer 1

You should always check it in "choose.php" (server-side) since the user can disable the JavaScript and post whatever they want in the inputs of your form

$college = mysql_real_escape_string($_GET['college']);
if ($college != "" || $college != null || $college != -1)
{
    //DO STUFF
}

NOTE: YOU SHOULD ALWAYS USE "mysql_real_escape_string" to prevent SQL Injection! more info: http://www.tizag.com/mysqlTutorial/mysql-php-sql-injection.php

So accordingly in search.php change the

$ac_term = "%".$_GET['term']."%";

to

$ac_term = "%". mysql_real_escape_string($_GET['term']) ."%";

You can also check the form before the user submit to just make it more user friendly (users don't want to wait couple of seconds for the page to gets refreshed with errors on it!)

so maybe something like this would help: Submit Event Listener for a form

function evtSubmit(e) {
  // code
  e.preventDefault();
 // CHECK IT HERE!
};

var myform = document.myForm;
myform.setAttribute('action', 'javascript:evtSubmit();');