Extend method in jquery

$.extend extends an object with one or more other objects, returning the object being extended. Parameter Type 1: Passing in only one object is an extension of the jquery tool method.

1     $ (function() {2        $.extend ({3             function(SMSG) {  4                console.log (SMSG); 5             }6        }); 7         $.console (' jquery ');//jquery8     });

Parameter Type 2: Passing in multiple objects is an extension of the first object.

1$(function(){2         varOtarget = {};3         4$.extend (Otarget, {name: ' Hum ')});5Console.log (Otarget.name);//Hum6         7$.extend (Otarget, {name: ' Hum '}, {age:20});8Console.log (Otarget.age);// -9         Ten$.extend (Otarget, {name: ' Hum '}, {name: ' Tyx ', age:20}); OneConsole.log (Otarget.name);//Tyx property with the same name will be overwritten A          -         //Note: The return value of $.extend () is an extended object -});

Parameter Type 3: The first parameter is a Boolean value, followed by multiple objects.

If the first argument is true, the copy is deep;

If the first argument is false, a shallow copy is performed (the default is a shallow copy), and the result is the same as when there is no Boolean argument, but the target object's value does not change (in other cases the target object and the returned result are the same object).

1$(function(){2         varOtarget = {courses: {math:100, english:80}};3Console.log ($.extend (otarget, {name: ' Hum ', courses: {math:50, chinese:99}}));//{name: ' Hum ', courses: {math:50, chinese:99}}4Console.log (Otarget);//{name: ' Hum ', courses: {math:50, chinese:99}}5 6         varOtarget = {courses: {math:100, english:80}};7Console.log ($.extend (false, Otarget, {name: ' Hum ', courses: {math:50, chinese:99}});//{name: ' Hum ', courses: {math:50, chinese:99}}8Console.log (Otarget);//{courses: {math:100, english:80}}9 Ten         varOtarget = {courses: {math:100, english:80}}; OneConsole.log ($.extend (true, Otarget, {name: ' Hum ', courses: {math:50, chinese:99, english:80}});//{name: ' Hum ', courses: {math:50, chinese:99, english:80}} AConsole.log (Otarget);//{name: ' Hum ', courses: {math:50, chinese:99, english:80}} -});

The difference between a deep copy and a shallow copy:

A deep copy causes all objects in the object to be recursively copied, and there is no referential relationship between the target object and the copied object;

A shallow copy does not allow the object to be recursively copied, and the object type properties of the target object and the layer within the copied object are referenced to each other.

1$(function(){2         varOtarget = {courses: {math:100, english:80}};3         varOcopy = {name: ' Hum ', courses: {math:50, chinese:99}};4Console.log ($.extend (Otarget, ocopy));//{name: ' Hum ', courses: {math:50, chinese:99}}5Console.log (Otarget);//{name: ' Hum ', courses: {math:50, chinese:99}}6Console.log (ocopy.courses = = otarget.courses);//True The Courses property of two objects points to the same object7OTarget.courses.chinese = 200;8Console.log (OCopy.courses.chinese);// $9 Ten         varOtarget = {courses: {math:100, english:80}}; One         varOcopy = {name: ' Hum ', courses: {math:50, chinese:99}}; AConsole.log ($.extend (true, Otarget, ocopy));//{name: ' Hum ', courses: {math:50, chinese:99, english:80}} -Console.log (Otarget);//{name: ' Hum ', courses: {math:50, chinese:99, english:80}} -Console.log (ocopy.courses = = otarget.courses);//False The Courses property of two objects no longer points to the same object theOTarget.courses.chinese = 200; -Console.log (OCopy.courses.chinese);// About -});

$.fn.extend when the method only passes an object, it is the extension to the $.fn. In other cases, as with the $.extend method, extend the object.

1 <Div>Content</Div>2 <Scriptsrc= "Jquery.js"></Script>3 <Script>4     $(function(){5 $.fn.extend ({6 ChangeColor:function(){7                 $( This). CSS ('Color', 'Blue');8             }9         });Ten         $('Div'). ChangeColor (); One     }); A </Script>

Extend method in jquery