Execute JavaScript function on a dynamic element (AJAX)

Question

Hello i have this following function:

... var model = $("#carModel");
.... model.change(validModel);

function validModel(){
     if(model.val() == 0){
            model.addClass("errorJS");
            return false;
            }else{
            model.removeClass("errorJS");
            return true;
            }  
    }

I am getting carmodel id from a select box generated after an AJAX call. I can get its value in the Firebug console, but the function doest not execute. Even tough i use model.livequery(validModel);

// The errorJS class puts a red border arround a element, if the function returns false

colinmarc · Accepted Answer · 2010-06-08 04:59:43Z

1

Among other problems, model means nothing inside the function context. Also, it makes no sense to call change(validModel) with this function, as it only returns a true/false value. You'll need to do something like:

model.change(function() {
    var truefalse = validModel(this);
    //do something with truefalse
});

and change the definition of validModel to

var validModel = function(elem){
   if($(elem).val() == undefined){
       $(elem).addClass("errorJS");
       return false;
   } else {
       $(elem).removeClass("errorJS");
        return true;
   } 
}

answered Jun 8, 2010 at 4:59

colinmarc

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7 Comments

colinmarc Over a year ago

also, your use of if val() = undefined doesn't ring true to me, but I can't remember off the top of my head if that's actually incorrect or just uncommon.

jartaud Over a year ago

Thanks for your help, ah sorry i used ..val()==0, i tried undefined, cause when i put alert(..val()) it returns undefined.

colinmarc Over a year ago

I think it would work with if (!val()). Also, I changed around my answer a bit to make more sense, hope that helps.

jartaud Over a year ago

Thanks again, but it still dies on new elements added by AJAX.

colinmarc Over a year ago

without seeing the ajax calls in question, or more of your code, I can't really help you. What do you mean, it "dies on new elements added by AJAX?"

|

jartaud · Accepted Answer · 2010-06-08 06:20:44Z

function getXMLHTTP() {
    var xmlhttp=false;  
    try{
    xmlhttp=new XMLHttpRequest();
    }
    catch(e){       
    try{            
    xmlhttp= new ActiveXObject("Microsoft.XMLHTTP");
    }
    catch(e){
    try{
    xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch(e1){
    xmlhttp=false;
      }
     }
  }
   return xmlhttp;
}

function getModel(idCar) {      
    var strURL="http://localhost/root509dir/Includes/model.php?idCar="+idCar;
    var req = getXMLHTTP();
    if (req) {
          req.onreadystatechange = function() {
          if (req.readyState == 4) {
          if (req.status == 200) {document.getElementById('modelCont').innerHTML=req.responseText;
     } else {
       alert("There was a problem while using XMLHTTP:\n" + req.statusText);
       }
    }               
}           
    req.open("GET", strURL, true);
    req.send(null);
    }       
}

model.php

if(isset($_GET['idCar'])){
    $idCar = mysql_real_escape_string($_GET['idCar']);
}
$modelQR = mysql_query("SELECT *FROM model WHERE from_make = '$idCar'") or die(mysql_error());?>
<?php echo htmlentities(PUB_AN_MOD); ?><em>*</em>
<select name="carmodel" id="carmodel">
<option value="0">----------------</option>
<?php while($model = mysql_fetch_array($modelQR)){?>
<option value="<?php echo htmlentities($model['id_model']);?>">
          <?php echo htmlentities($model['car_model']);?></option>
<?php }?>
</select>

cars.php

<?php
$QRcars = mysql_query("SELECT *FROM car ORDER BY car_make") or die(mysql_error());
if(mysql_num_rows($QRcars)>0){?>
<select name="cars" id="cars" onchange="getModel(this.value);"><option value="0">-------------------</option>
<?php while($cars = mysql_fetch_array($QRcars)){?>
<option value="<?php echo htmlentities($cars['id_car']);?>">
<?php echo htmlentities($cars['car_make']);?></option>
<?php }?>
</select>       
<?php }?>
<span id="modelCont">
<?php echo htmlentities(PUB_AN_MOD); ?><em>*</em>
<select name="model" id="model">
<option value="0">---------</option>
</select>
</span>

jartaud · Accepted Answer · 2010-07-24 03:22:53Z

0

I got it, the problem was with the ready event, i defined the function out of it and voila.

answered Jul 24, 2010 at 3:22

jartaud

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