this.initialize.apply(this, arguments)这句话的含义

Question

 

function ZoomPic ()
{
    this.initialize.apply(this, arguments)    
}
ZoomPic.prototype = 
{
    initialize : function (id){}
}
    
           
        

看了一些别的资料，还是不是很清楚this.initialize.apply(this, arguments)这句话的含义，还有initialize : function (id)为什么不写成initialize = function (id)