jQuery

addClass() method of Jquery

Adding a class to an element in jquery is very simple.  The classes can be added using addClass() method. One or more classes can be added to element. Single class can be added to multiple elements. The following example shows adding single class to multiple elements and also adding more than one class to single element.

 

On click output will be :

removeClass() method of Jquery

The classes can be removed using removeClass() method. One or more classes can be removed of an element.The following example shows removing single class of multiple elements and removing more than one class of single element.

Above same example is modified to remove the classes.

 

On click output will be :

jQuery and AJAX

jQuery provides several methods for AJAX functionality.

By using jQuery AJAX methods, we can get text, HTML, XML, or JSON from the server using either HTTP Get or HTTP Post . We can load the external data directly into the selected HTML elements of your web page.

Now let’s see how we can load the external data directly into a selected HTML element of our page using jQuery AJAX methods.

Here in the below example we have myPage.html file which will invoke the jQuery AJAX method to load the data from another HTML file called myData.html

Make sure that you have jquery-1.8.2.js saved under the folder script.

myPage.html

 

myData.html

Output:

Here you can notice that when you click on Get Data button , You are getting data from myData.html.

$(“#myBtn”).click(function(){  //This will trigger the click action on myBtn
$(“#myDiv”).load(“myData.html a:eq(0)”, function(response,status,xhr){ // will load the value of  first  Anchor tag in data .html
if(status == “error”){
alert(xhr.statusText)
}
});
})

 

It is very easy to add css using jQuery. Lets understand this by different examples below.

Example 1:

Adding css for <li> tag

Output

Here  you can notice that the css is applied for all the <li>.

Example 2:

Adding multiple style properties.

Output

Here  you can notice that the margin and border properties are applied for all the <li>.

Example 3 :

Adding css for a particular ID.

Output

Here  you can notice that css is applied for all the tags coming under the id ‘item 1’.

What is jQuery

jQuery is a JavaScript Library which simplifies JavaScript programming, HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.

Your first jQuery code

Lets see an example which will popup an alert while loading the page using jQuery.

 

Here you can notice that we have included a java script file –  jquery-1.8.2.js , Which provides many features. You can download this js file from jQuery website.

 

jQuery provides a shortcut ‘$ ‘ for window.jQuery(“document”).ready , By which we can rewrite the code as below.