![Arrays
You can define arrays using the array literal as follows:
var x = [];
var y = [1, 2, 3, 4, 5];
An array has a length property that is useful for iteration:
var x = [1, 2, 3, 4, 5];
for (var i = 0; i < x.length; i++)
{
do something;
}
By- Tajendar Arora](https://image.slidesharecdn.com/jquerypptshare-151221133302/85/Introduction-to-Jquery-7-320.jpg)
Introduction to Jquery
- 2. What is jQuery? •jQuery is an Open-Source JavaScript framework that simplifies cross-browser client side scripting. •Animations •DOM manipulation •AJAX •Extensibility through plugins •jQuery was created by John Resig and released 01/06 •Most current release is 1.4.2 (2/19/10) By- Tajendar Arora
- 3. Javascript is not a good language design Javascript has become bloated DOM navigation Browser differences Writing Javascript code is tedious, time-consuming, and error-prone By- Tajendar Arora
- 4. Who Uses jQuery? Google Amazon IBM Microsoft Twitter Dell docs.jquery.com/Sites_Using_jQuery By- Tajendar Arora
- 5. jQuery exists as a single external JS file. You can run jQuery one of two ways: Download the file to your computer Link to a remotely hosted version from a reliable and established website Each option has its pros and cons Download: The main benefit is that if you are offline, the file will still be there on your computer when you are developing your code. Link:These externally linked files are typically the most up to date. <script src= "http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">< /script> Remember that this link must go in the ‘head’ section of your HTML file. Note that the closing </script> tag IS required. By- Tajendar Arora
- 6. jQuery is a framework built using JavaScript capabilities. So, you can use all the functions and other capabilities available in JavaScript String Numbers Boolean Objects JavaScript supports Object concept very well.You can create an object using the object literal as follows: var emp = { name: "Zara", age: 10 }; // Getting object properties emp.name // ==> Zara // Setting object properties emp.name = "Daisy" // <== Daisy By- Tajendar Arora
- 7. Arrays You can define arrays using the array literal as follows: var x = []; var y = [1, 2, 3, 4, 5]; An array has a length property that is useful for iteration: var x = [1, 2, 3, 4, 5]; for (var i = 0; i < x.length; i++) { do something; } By- Tajendar Arora
- 8. Functions A function in JavaScript can be either named or anonymous. A named function can be defined using function keyword as follows: function named(){ // do some stuff here } An anonymous function can be defined in similar way as a normal function but it would not have any name. An anonymous function can be assigned to a variable or passed to a method as shown below. var handler = function (){ // do some stuff here } JQuery makes a use of anonymous functions very frequently as follows: $(document).ready(function(){ ……………….} By- Tajendar Arora
- 9. Context JavaScript famous keyword this always refers to the current context. Example $("div").click(function() { // this refers to a div DOM element }); By- Tajendar Arora
- 10. Scope The scope of a variable is the region of your program in which it is defined. JavaScript variable will have only two scopes. Global Variables: A global variable has global scope which means it is defined everywhere in your JavaScript code. Local Variables: A local variable will be visible only within a function where it is defined. Function parameters are always local to that function. By- Tajendar Arora
- 11. Callback A callback is a plain JavaScript function passed to some method as an argument or option. Some callbacks are just events, called to give the user a chance to react when a certain state is triggered. jQuery's event system uses such callbacks everywhere for example: $("body").click(function(event) { console.log("clicked: " + event. target); }); By- Tajendar Arora
- 12. Callback A callback is a plain JavaScript function passed to some method as an argument or option. Some callbacks are just events, called to give the user a chance to react when a certain state is triggered. jQuery's event system uses such callbacks everywhere for example: $("body").click(function(event) { console.log("clicked: " + event. target); }); By- Tajendar Arora
- 13. Okay, let’s get started with our first jQuery function! We will begin with a function called ‘ready()’, or more specifically, document.ready() •The ‘ready’ function executes after the entire web page has finished loading in the visitor’s browser. You will typically include this function on every page in which you are using jQuery. <script> $(document).ready( function() { // Some jQuery code will // go in here... } ); </script> By- Tajendar Arora