Jquery Chosen Select plugin doesn't Work in PHP Ajax response - php

Question

I have two chosen select box for fetching values from MYSQL DB
When No-1 Select box change then No-2 select box generate from AJAX response.
Chosen Plugin in No-1 work perfectly. But When No-2 select box generate from ajax then chosen plugin doesn't work in No-2 select box.
Main.PHP
<div class="control-group">
<label for="textfield" class="control-label">Category<span>*</span></label>
<div class="controls">
<select name="category" id="category" multiple="multiple" class="chosen-select input-medium" required onchange="showSubCat(this.value)">
<option value='1'>Option 1</option>
<option value='2'>Option 2</option>
</select>
<input type='hidden' value='' id='categoryId' name='categoryId'>
</div>
</div>
<div class="control-group">
<label for="textfield" class="control-label">Sub Category</label>
<div class="controls">
<select name="subCat_2" id="subCat_2" multiple="multiple" class="chosen-select input-large">
<option value="">--- Select Sub Category---</option>
</select>
</div>
</div>
JS CODE :
var xmlhttp;
function showSubCat(str){
if( $('#category :selected').length > 0){
//build an array of selected values
var selectednumbers = [];
$('#category :selected').each(function(i, selected) {
selectednumbers[i] = $(selected).val();
});
}
//alert(selectednumbers);
document.getElementsByName('categoryId')[0].value = selectednumbers;
if (str==""){
document.getElementById("subCat_2").innerHTML="";
return;
}
if (window.XMLHttpRequest){
xmlhttp=new XMLHttpRequest();
}
else{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState==4 && xmlhttp.status==200){
document.getElementById("subCat_2").innerHTML=xmlhttp.responseText;
//alert(xmlhttp.responseText);
console.log(xmlhttp.responseText);
}
}
xmlhttp.open("GET","MYurl.php?catId="+selectednumbers,true);
xmlhttp.send();
}
AJAX.PHP
echo "<option value=''>--- Select Sub Category --- </option>";
$sql="SELECT field FROM tableName WHERE condition;
$result = mysql_query($sql) or die('MySql Error' . mysql_error());
while($row = mysql_fetch_array($result)){
echo "<option value='1'> ----- Sub Option 1</option>";
}
Let me know what i have done Wrong..??

Answer 1

Assuming you're calling chosen on the 2nd list, try using
$('#subCat_2').trigger('chosen:updated');
after you update its list.
If you look at plugin page it indicates that
`You can trigger several events on the original select field to invoke a behavior in Chosen.
chosen:updated This event should be triggered whenever Chosen’s underlying select element changes (such as a change in selected options).`

Answer 2

You need to rebuild the selectbox with new data in it.
if (xmlhttp.readyState==4 && xmlhttp.status==200){
// bind new data
document.getElementById("subCat_2").innerHTML=xmlhttp.responseText;
// refresh chosen.
$('#subCat_2').trigger("chosen:updated");
}