JQuery UI Interview Questions And Answers

jQuery UI is a JavaScript library that provides abstractions for low-level interaction and animation, advanced effects and high-level, themeable widgets, built on top of the jQuery JavaScript library, that can be used to build interactive web applications. It was released in September 2007, announced in a blog post by John Resig on jquery.com. The latest release, 1.10.4, requires jQuery 1.6 or later.

Jquery is lightweight javascript library file.
Jquery run in all browsers.
Jquery is client side scripting language.
Jquery browser depended framework.
Jquery developed by javascript.

Jquery combined with other java script libraries like prototype, mootools that time Jquery coding will be conflict with other libraries.
So that time use this command for non -conflict jquery with other java script libraries.
jQuery.noConflict();

Include jquery library in the head section of page. Then use below code.
$(“#id”).val();
jQuery(“#id”).val();

Please follow below code to submit a form by ajax using jquery

$(‘#formid).submit(function() {
$.ajax({
type: “POST”,
url: “back.php”,
data: “name=php&location=india”,
success: function(msg) {
alert( “Data Saved: ” + msg );
}
});
}

Where formid is the form ID.”POST” is the method by which you want to send data.You can also use “GET” method.”back.php” is the php file which you want to call.”name=php&location=india” This is values of control. success: function(msg){ alert (“Data Saved: ” + msg); } This is a success function, This will execute after success of you post.Often in Ajax back.php does not refresh because this is cached by browser. To avoid this issue add [cache: false,] in above code.Loads data synchronously. Blocks the browser while the requests is active. It is better to block user interaction by other means when synchronization is necessary.

To avoid this issue add [async: false,] in above code.

This is example to apply css on a div element which have id name myDivId.
$(”#myDivId “).css(”border”,”3px solid red”);
To apply css on all div elements use below code.$(“div”).css(“border”,”3px solid red”);

Where$(“div”) pointing all div elements in the page.For You need to use.$(”P”) on above code.

Suppose that Css class has following defination
.class
{
font-size:10px;
font-weight:normal;
color:#000000;
}

now we want to add border property on above class, so we should follow below code.

$(“.class”).css(“border”,”1px solid blue”);
Where $(“.class”) name of css class. Now .class will automatically add border property in his class definition.

$(”tr:last”).css({backgroundColor: ‘yellow’, fontWeight: ‘bolder’});

$(”tr:even”).css(”background-color”, “#bbbbff”);

$(”tr:odd”).css(”background-color”, “#bbbbff”);

Dollar Sign is nothing but it’s an alias for JQuery. Take a look at below jQuery code
$(document).ready(function(){
});
Over here $ sign can be replaced with “jQuery ” keyword.
jQuery(document).ready(function(){
});

Document.ready() function is different from body onload() function because off 2 reasons.
1. We can have more than one document.ready() function in a page where we can have only one onload function.

2. Document.ready() function is called as soon as DOM is loaded where body.onload() function is called when everything gets loaded on the page that includes DOM, images and all associated resources of the page.

It’s really simple. One just need to add reference of javascript file(.js). Go to Jquery.com and download the latest version of jQuery. When download is completed, there is a “jQuery-1.3.2.js” in the folder. Include this file and you good to go now for JQuery.

Features of Jquery
1. One can easily provide effects and can do animations.
2. Applying / Changing CSS.
3. Cool plugins.
4. Ajax support
5. DOM selection events
6. Event Handling

JQuery UI is a library which is built on top of JQuery library. JQuery UI comes with cool widgets, effects and interaction mechanism.

Some of the common methods are :
1. Show()
2. Hide()
3. Toggle()
4. FadeIn()
5. FadeOut()

There are 3 types of selectors in Jquery
1. CSS Selector
2. XPath Selector
3. Custom Selector