Where is the hasClass method?
June 25th, 2007
A common question on the jQuery mailing list is: "Where is the hasClass method?". jQuery has a very flexible method named is. This method takes an expression to test against. For example you could see if a particular element is a form element.
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$('#myElement').is('form');
This will return true or false if the element is a form or not. This method is pretty flexible and makes sense but it can be a little hard to find. We can check to see if an element is of a particular class (or has a class name) by simply using a class selector/expression.
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$('#myElement').is('.myClass');
Again, this will return true or false if the element has the class name 'myClass' or not.
Even better in the upcoming jQuery 1.1.3, the is method can take a comma separated list to test against.
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$('#myElement').is('.myClass, .myOtherClass');
This will return true if the element has either 'myClass' or 'myOtherClass', otherwise it returns false.
Even though the is method is flexible and can check for a class it can be helpful to have an actual hasClass method. Actually a hasClass method is currently on the table for inclusion in jQuery 1.2. Here is a hasClass method that you can include in your code now.
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jQuery.fn.hasClass = function(c) {
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return this.is('.'+c)
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};
You can download the source code and see an example here for this hasClass method.
June 25th, 2007 at 6:10 pm
Hey Brandon, excellent entry! You're right, this (.)is an oft-requested method on the list (sorry for the ridiculously bad play on words). Great to see that you've often an easy-to-implement option for those who are looking for
hasClass!July 26th, 2007 at 9:18 am
Cheers, I wasn't aware of how .is() works - very useful.