jQuery 1.6+
jQuery added a :focus
selector so we no longer need to add it ourselves. Just use $("..").is(":focus")
jQuery 1.5 and below
Edit: As times change, we find better methods for testing focus, the new favorite is this gist from Ben Alman:
jQuery.expr[':'].focus = function( elem ) {
return elem === document.activeElement && ( elem.type || elem.href );
};
Quoted from Mathias Bynens here:
Note that the (elem.type || elem.href)
test was added to filter out false positives like body. This way, we make sure to filter out all elements except form controls and hyperlinks.
You're defining a new selector. See Plugins/Authoring. Then you can do:
if ($("...").is(":focus")) {
...
}
or:
$("input:focus").doStuff();
Any jQuery
If you just want to figure out which element has focus, you can use
$(document.activeElement)
If you aren't sure if the version will be 1.6 or lower, you can add the :focus
selector if it is missing:
(function ( $ ) {
var filters = $.expr[":"];
if ( !filters.focus ) {
filters.focus = function( elem ) {
return elem === document.activeElement && ( elem.type || elem.href );
};
}
})( jQuery );
Best Answer
Actually the example you gave for focusing on this site works just fine, as long as you're not focused in the console. The reason that's not working is simply because it's not stealing focus from the dev console. If you run the following code in your console and then quickly click in your browser window after, you will see it focus the search box:
As for your other one, the one thing that has given me trouble in the past is order of events. You cannot call focus() on an element that hasn't been attached to the DOM. Has the element you are trying to focus already been attached to the DOM?