jquery not working correctly in plugin options page?

Question

I have created my own plugin which has a custom script attached to it. I have added this in the correct manor like this:

add_action('admin_enqueue_scripts', 'add_search_script');
function add_search_script() {
    wp_register_script('search', plugins_url('search.js', __FILE__) );
    wp_enqueue_script('search');    
}

If i add an alert to the top of the .js file, and then refresh the plugin page the alert appears. Simple alert like this:

alert ('test');

However if i try and hide something with js, noting happens?

I target a class like this:

$(".simple").hide();

Which has no effect? I have also tried:

jQuery(".simple").hide();

Which again has no effect?

Any ideas on what could be the problem?

Answer 1

If your script is loading in the head of your admin page I would recommend wrapping your code in a document ready function

// wait till the entire dom is available before executing JS
// notice the $ this brings the $ into private scope if you wish to use it
jQuery(document).ready(function($){ 

    // put your page code here
    $(".simple").hide();

});