jQuery extend 命名空间 each 等讲解

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1.extend 扩展

① 基本扩展

extend(dest,src1,src2,src3...);var newSrc=$.extend({},src1,src2,src3...)//也就是将"{}"作为dest参数

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

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

② 省略dest参数

 $.extend({  hello:function(){alert('hello');}  });//合并到jQuery全局对象中

$.fn.extend({  hello:function(){alert('hello');} });//合并到jQuery实例对象中

   <script type="text/javascript">   $(document).ready(function (){$.extend({jqueryAlert:function(){alert("jQuery类method!");}});$.fn.extend({            alertWhileClick:function(){    alert("jQuery对象method!");         }        }); $.jqueryAlert();});   </script>//比较

③ 基本扩展和深入扩展

//基本扩展; var newSrc1 = jQuery.extend(       { name: "jonh", location: { city: "Boston" } },       { last: "Resig", location: { state: "MA" } }     );   alert(newSrc1.location.city);  //深入扩展;   var newSrc2 = jQuery.extend( true,     { name: "John", location: { city: "Boston" } },       { last: "Resig", location: { state: "MA" } }    );    alert(newSrc2.location.city);

深入扩展后,location中的属性变成了两个,而基本扩展确实覆盖

2.命名空间

① net 中有json数据

 $.extend({net:[{name:"ggf"},{name:"jack"}]});   $.extend($.net,{    hello:function(){alert('hello');}   });   $(document).ready(function(){$.net.hello();alert($.net[1].name);});

② net 中没有json数据

 $.extend({net:{}});   $.extend($.net,{    hello:function(){alert('hello');}   });   $(document).ready(function(){$.net.hello();alert($.net[1].name);});

3.jQuery each 函数

$.each([1,2,3],function(i,val){//var 就是循环到的实体;//alert(i);次数//alert(val);值});var obj = { one:"o", two:"t", three:"r", four:"f"};     $.each(obj, function(key, val) {    //alert(val.one);error    //alert(val.key);error    //alert(obj.key);error    //alert(obj.one);o o o o      //alert(key);  one two three four     //alert(val);o t r f}); var obj2 = [{name:"Jack",age:22},{name:"Marry",age:21}];$.each(obj2, function(key, val) { //alert(key);1 2//alert(val.name);Jack Marry//alert(obj2[1].age);}); }

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