Category: Code 101

jQuery uses the same selectors as CSS. This makes it very easy to select the elements you want to work with. The two most commonly used selectors are id and class. So before we start make sure you have your jQuery setup and the $(document).ready() function on the page.

Selecting by ID

This is best used when you want to target one specific element. The selector is exactly the same as what you would use to set styles for the particular element in CSS.

Selecting element with CSS and setting some styles.

#youridhere {
	display: none;
}

Now selecting the same element with jQuery and adding CSS styles.

$("#youridhere").css("display","none");

Selecting by Class

With the class selector you can select multiple elements at once. jQuery deals with multiple elements in a very simple manor. It returns an array of jQuery objects. With the way jQuery is designed it will automaticaly apply anything you do to your selection to all elements without having to loop threw the results.

Lets take a simples example of hiding all elements with a class of hide. To do this with CSS we would create the class in our style sheet like so:

.hide {
	display: none;
}

To do this same thing to all the elements with the class of hide in jQuery. You would use the following statement:

$(".hide").css("display","none");

This should get you started on the path of using jQuery in your projects. To read more about the selectors your can use in jQuery check out the documentation.

Lets face it, nobody likes all those javascript:void(0); in the anchors href. As for that body “onload” function call, can that too, its no good. All that ugly code in the markup is just plain bad news.

With jQuery and document.ready() you can put all your event driven javascript in one file, making it easy to maintain and upgrade later. The document.ready() function works just as the name implies. Document refers to the DOM, or Document Object Model, while in this case “ready” refers to when the DOM is registered by the browser.

Before we start, make sure you have jQuery included on your page. For a quick refresh on how that’s done, click here.

Using the document.ready() function is really easy. Check out this example:

	$(document).ready(function(){
		//insert code here
		alert("this will flre when the DOM is loaded.");
	});

As with most code, there is a shorthand version of the document.ready() function. In jQuery, any function passed to the jQuery object will be bound to the document.ready() function, as seen below.

	$(function(){
		//insert code here
		alert("this will work the same as the code above.");
	});

This is how you would add a click event to all the anchor tags on your page using the document.ready() function.

	$(document).ready(function(){
		$('a').click(function(){
			alert("you clicked me!");
		});
	});

That’s all there is to it. Are you having an issue with jQuery, or any code you need some help on? Have an idea for an article you’d like to see? Feel free to leave a comment with any questions or suggestions.