1.javascript 选项散列对象

   function Test(p1,p2,p3,p4,p5){

    //do something

  }

  call:

  参数可选

   Test({

   p1:value1,

   p2:value2,

   p5:value5

    });

 2. self-definition function

 Test(options){

　　var settings = $.extend({

       p1:value1,

       p2:value2,

       p3:value3,

       p4:value4,

       p5:value5

   },options||{});

  //do something

}