原生拖放

var dragDom = document.querySelector( ".forDrop" ),
            dropDom = document.querySelector( ".forDrop" );

W.addHandler( dragDom, "dragstart", function ( e ) {
        e.dataTransfer.setData("text","hello zodiac");
        W.log( "dragstart" );
    } );
    W.addHandler( dragDom, "drag", function ( e ) {
        W.log( "drag" );
    } );
    W.addHandler( dragDom, "dragend", function ( e ) {
        W.log( "dragend" );
    } );

W.addHandler( dropDom, "dragenter", function ( e ) {
        W.preventDefault( e );
        W.log( "dragenter" );
    } );
    W.addHandler( dropDom, "dragover", function ( e ) {
        W.preventDefault( e );
        W.log( "dragover" );
    } );
    W.addHandler( dropDom, "drop", function ( e ) {
       var data=e.dataTransfer.getData("text");
        W.preventDefault( e );
        W.log( "drop" );
    } );
    W.addHandler( dropDom, "dragleave", function ( e ) {
        W.preventDefault( e );
        W.log( "dragleave" );
    } );

//包装的拖放

function EventTarget() {
this.handlers = {};
}

EventTarget.prototype = {
constructor : EventTarget,
addHandler : function ( type, handler ) {
if ( typeof this.handlers[type] == "undefined" ) {
this.handlers[type] = [];
}
this.handlers[type].push( handler );
},

fire : function ( event ) {
if ( !event.target ) {
event.target = this;
}
if ( this.handlers[event.type] instanceof Array ) {
var handlers = this.handlers[event.type];
for ( var i = 0, len = handlers.length; i < len; i++ ) {
handlers[i]( event );
}
}
},

removeHandler : function ( type, handler ) {
if ( this.handlers[type] instanceof Array ) {
var handlers = this.handlers[type];
for ( var i = 0, len = handlers.length; i < len; i++ ) {
if ( handlers[i] == handler ) {
break;
}
}
handlers.splice( i, 1 );
}
}
};
var target = new EventTarget();

//添加一个message事件处理器
// target.addHandler("message",handleMessage);

//添加一个message事件处理器
// target.addHandler("message",handleMessage1);

//触发所有message事件处理器
// target.fire({type:"message",message:"Hello World"});

//触发一个message事件处理器
// target.removeHandler("message",handleMessage);

//触发所有message事件处理器
//target.fire({type:"message",message:"Hello World1"});

//endregion

//region拖放
var DragDrop = function () {
var dragDrop = new EventTarget(),
dragging = null,
diffX = 0,
diffY = 0;

function handleEvent( event ) {
//获取事件和对象
event = W.getEvent( event );
var target = W.getEventTarget( event );

//确定事件类型
switch ( event.type ) {
case "mousedown":
if ( target.className.indexOf( "draggable" ) > -1 ) {
dragging = target;
diffX = event.clientX - target.offsetLeft;
diffY = event.clientY - target.offsetTop;
dragDrop.fire( {type : "dragstart", target : dragging, x : event.clientX, y : event.clientY} );
}
break;
case "mousemove":
if ( dragging != null ) {

//指定位置
dragging.style.left = (event.clientX - diffX) + "px";
dragging.style.top = (event.clientY - diffY) + "px";

dragDrop.fire( {type : "drag", target : dragging, x : event.clientX, y : event.clientY} );
}
break;
case "mouseup":
dragDrop.fire( {type : "dragend", target : dragging, x : event.clientX, y : event.clientY} );
dragging = null;

break;
default :
break;
}
}

//公共接口
dragDrop.enable = function () {
W.addHandler( document, "mousedown", handleEvent );
W.addHandler( document, "mousemove", handleEvent );
W.addHandler( document, "mouseup", handleEvent );
};
dragDrop.disable = function () {
W.removeHandler( document, "mousedown", handleEvent );
W.removeHandler( document, "mousemove", handleEvent );
W.removeHandler( document, "mouseup", handleEvent );
};
return dragDrop;
}();

DragDrop.addHandler( "dragstart", function ( e ) {
W.log( e.x );
} );
DragDrop.addHandler( "drag", function ( e ) {
W.log( e.x );
} );
DragDrop.addHandler( "dragend", function ( e ) {
W.log( e.x );
} );
document.querySelector( ".aa" ).classList.add( "draggable" );
DragDrop.enable();