JS Object-Oriented Programming 2

Define Backtop, reference Scrollto

define ([' jquery ', ' Scrollto '],function ($,scrollto) {

function Backtop (el,opts) {//define Constructor

This.opts=$.extend ({},backtop.defaults,opts);

this. $el =$ (EL);

This.scroll=new Scroll. ScrollTo ({

dest:0,

Speed:this.opts.speed

})

This._checkposition ();

$ (window). On (' scroll ', $.proxy (this._checkposition,this));

if (this.opts.mode== ' move ') {

this. $el. On (' Click ', $.proxy (this._move,this));

}else{

this. $el. On (' Click ', $.proxy (this._go,this));

}

}

Backtop.prototype._move=function () {

This.scroll.move ();

}

Backtop.prototype._go=function () {

This.scroll.go ();

}

Backtop.prototype._checkposition=function () {

var $el =this. $el;

if ($ (window). scrolltop () >this.opts.pos) {

$el. FadeIn ();

}else{

$el. FadeOut ();

}

};

return{

Backtop:backtop;

}

})

JS Object-Oriented Programming 2