how to run an onchange function when page is loaded if the selected box is already selected

Question

Im running into a problem where i have an ajax driven page that is drawn when a user selects something from a simple drop down: ``` ``` and the remainder of the page is drawn using the jquery `.change()` : ``` $('#selectdepartment').change(function(){ }); ``` Which then runs some ajax to php script. everything works great, the problem is when i submit a form that was drawn with ajax (using `$_SERVER['PHP_SELF'];`), the data gets submited, the page reloads, and the page is cleared but the select box is still left where it was. The user has to move to a different option then back to the one the selected originally to re-fire the `.change()`. that sucks. I could fix this by passing a php variable in all of my forms, then checking to see the variable set on every page load and if it is draw the page parts then, but this would lead to pretty messy code and it's less than desirable. There has…

Accepted Answer

You can use the `.trigger()` function to immediately trigger the `change` event handler when the page has loaded:

```
$('#selectdepartment').change(function() {
    // code here
}).trigger('change');
```

Or if you need to call it elsewhere via JavaScript/jQuery:

```
$('#selectdepartment').trigger('change'); // or just .change() as a shorthand
```

how to run an onchange function when page is loaded if the selected box is already selected

Solution

Problem