Q:

How do I get a jQuery selector's expression as text?

I have a jQuery selector, which has a chained function.
Inside the function I want to get access to the TEXT representing the expression for the selector.
$("cat dog").function() {

    // how do I get access to the "cat dog" string from inside THIS function ?
};

I've over simplified in this code sample what I actually want to do. I'm writing a plug-in and I need access to the selector for which the wrapped set has been created. Obviously in this particular example I have access to "cat dog" becasue i wrote it. So just picture this being in a plugin.
Its a little tricky to google for this.
edit: the 'selector' property is unfortunately now deprecated. http://jquery.com/upgrade-guide/1.9/#selector-property-on-jquery-objects

A:

There is a 'selector' attribute in the jQuery object, but I'm not sure it's always available.

A:

This is far from optimal but works in some cases. You could do the following:
jQuery.fn._init = jQuery.fn.init
jQuery.fn.init = function( selector, context ) {
    return (typeof selector === 'string') ? jQuery.fn._init(selector, context).data('selector', selector) : jQuery.fn._init( selector, context );
};

jQuery.fn.getSelector = function() {
    return jQuery(this).data('selector');
};

This will return the last selector used for the element. But it will not work on non existing elements.
<div id='foo'>Select me!</div>
<script type='text/javascript'>
 $('#foo').getSelector(); //'#foo'
 $('div[id="foo"]').getSelector(); //'div[id="foo"]'
 $('#iDoNotExist').getSelector(); // undefined
</script>

This works with jQuery 1.2.6 and 1.3.1 and possibly other versions.  
Also:
<div id='foo'>Select me!</div>
<script type='text/javascript'>
 $foo = $('div#foo');
 $('#foo').getSelector(); //'#foo'
 $foo.getSelector(); //'#foo' instead of 'div#foo'
</script>

Edit
If you check immidiatly after the selector has been used you could use the following in your plugin:
jQuery.getLastSelector = function() {
    return jQuery.getLastSelector.lastSelector;
};
jQuery.fn._init = jQuery.fn.init
jQuery.fn.init = function( selector, context ) {
    if(typeof selector === 'string') {
        jQuery.getLastSelector.lastSelector = selector;
    }
    return jQuery.fn._init( selector, context );
};

Then the following would work:
<div id='foo'>Select me!</div>
<script type='text/javascript'>
 $('div#foo');
 $.getLastSelector(); //'#foo'
 $('#iDoNotExist');
 $.getLastSelector(); // #iDoNotExist'
</script>

In your plugin you could do:
jQuery.fn.myPlugin = function(){
 selector = $.getLastSelector;
 alert(selector);
 this.each( function() {
  //do plugins stuff
 }
}

$('div').myPlugin(); //alerts 'div'
$('#iDoNotExist').myPlugin(); //alerts '#iDoNotExist'

But still:
$div = $('div');
$('foo');
$div.myPlugin(); //alerts 'foo'

A:

If you're using firebug you could console.log(this) inside the function and see if the selector string is accessible somewhere in the object. Sorry I am not familiar with the jQuery API.

