Jquery extend function

jQuery.extend function introduction

JQuery.extend Extension method：
    Extension method of jQuery extend is usually method when write plugin，
      一、jquery prototype method　　　

extend(dest,src1,src2,src3...);

      it mean merge src1 src2 src3 into dest,result is dest merged,It can be seen that after according to methods ,the dest already modify。if you want't get  modified dest，you can use ：

var newSrc=$.extend({},src1,src2,src3...)

      So you can merge SRC1, src2, src3...。

for example：

var result=$.extend({},{name:"Tom",age:21},{name:"Jerry",sex:"Boy"})

 

      and result is 

result={name:"Jerry",age:21,sex:"Boy"}

      It meas the later element will cover front element

      二、omit dest
      for example:
 　　1、$.extend(src)
 　　the way can merge the attribution into jquery object：

$.extend({
hello:function(){alert('hello');}
});

 　　
 　　2、$.fn.extend(src)
 　　　the way can merge the attribution into jquery prototype:

$.fn.extend({
hello:function(){alert('hello');}
});

 

　　 

 　　list some example under：

$.extend({net:{}});

 

　　 this is way that can extent net space in jquery global objec

$.extend($.net,{
hello:function(){alert('hello');}
})

  　　

 　　三、Jquery.extend方法also have one prototype：  

extend(boolean,dest,src1,src2,src3...)

      first params boolean is represent whether if deep copy,for example:

var result=$.extend( true, {}, 
{ name: "John", location: {city: "Boston",county:"USA"} }, 
{ last: "Resig", location: {state: "MA",county:"China"} } );

      we can seen object of src1 location:{city:"Boston"},object of src2 location:{state:"MA"},merge result is:： 

result={name:"John",last:"Resig",
location:{city:"Boston",state:"MA",county:"China"}}

 

       so it will merge nested object in src,if first boolean is false，we look ，for example：

var result=$.extend( false, {}, 
{ name: "John", location:{city: "Boston",county:"USA"} }, 
{ last: "Resig", location: {state: "MA",county:"China"} } 
);

    result is:

result={name:"John",last:"Resig",location:{state:"MA",county:"China"}}