> In fact, if you find yourself doing a lot of if(something exists) {
> ... } else { ...}, you might want to consider trying to move some of
> your code into a plugin.
The target audience for an exists() function would be new comers to
jQuery. Those are generally a little scared about writing their own
'plugin' even so there isn't much to be scared about I think and I'm
just making this assumption here ; ).
Anyway, there are situations where plugins are not enough. For example
if you have to modify other elements in case a certain screen element
exists then a plugin won't really help you a lot unless it's very
app-specifc.
-- Felix
--------------------------
My Blog: http://www.thinkingphp.org
My Business: http://www.fg-webdesign.de
Erik Beeson wrote:
>
> In fact, if you find yourself doing a lot of if(something exists) {
> ... } else { ...}, you might want to consider trying to move some of
> your code into a plugin. Most jQuery functions/plugins already deal
> with the if(exists)... part by simply not executing if nothing is
> selected. If you really want the 'else' part, you could imagine a
> simple plugin, something like (untested):
>
> $.fn.ifEmpty = function(f) {
> if(this.length == 0) f.apply(this);
> return this;
> }
>
> And use it like this:
>
> $('#foo').show().ifEmpty(function() {
> alert("foo doesn't exist");
> });
>
> Which would show the element with ID foo, or show an alert if the
> element doesn't exist. Equivalent to:
>
> var $foo = $('#foo');
> if($foo.length > 0) {
> $foo.show();
> } else {
> alert("foo doesn't exist");
> }
>
> Just an idea.
>
> --Erik
>
>
> On 7/9/07, Erik Beeson <[EMAIL PROTECTED]> wrote:
>> > Another idea is that if the seletor doesn't select any elements,
>> > return null (as does getElementById() in that case):
>> > ...
>> > but that may not be backward compatible. Of what use is an empty
>> > jQuery object?
>>
>> An empty jQuery object doesn't break chainability:
>>
>> $('#foo').hide();
>>
>> Will hide the element with ID foo if it exists. Otherwise, it does
>> nothing. If null were returned, that would generate a javascript
>> error, so you would have to always check for the existence of the
>> element if you wanted to be sure you didn't generate an error.
>>
>> This is one of the sweetest features of jQuery.
>>
>> --Erik
>>
>
