发布于 2016-12-27 10:53:52 | 111 次阅读 | 评论: 0 | 来源: 网友投递
这里有新鲜出炉的Javascript教程,程序狗速度看过来!
JavaScript客户端脚本语言
Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言,主要目的是为了解决服务器端语言,比如Perl,遗留的速度问题,为客户提供更流畅的浏览效果。
/*
*使用方法:
* var d = new Drag({id:'dragPannel',maxLeft:500,maxTop:200});
* d.ready();
*请注意:
* 拖动对象的left和top样式必须写在其style属性里边
*
*/
//矫正调用者。将 fn 作为 newObj 的方法调用
function repairCaller(newObj, fn){
return function(){
return fn.apply(newObj, arguments);
}
}
function Drag( config ){
this.moveTarget = T.dom.get( config.id );
this.startLeft = parseInt(this.moveTarget.style.left); //每次拖动开始时被拖动对象的 left,top
this.startTop = parseInt(this.moveTarget.style.top);
this.startClientX = this.startLeft; //保存拖动开始时事件的 clientX, clientY
this.startClientY = this.startTop;
this.MAX_LEFT = config.maxLeft||document.documentElement.clientWidth - this.moveTarget.offsetWidth; //元素可以移动的最大范围
this.MAX_TOP = config.maxTop||document.documentElement.clientHeight - this.moveTarget.offsetHeight;
this.lock = true;
}
Drag.prototype.ready = function(){
//绑定事件
T.bind(document, "mousedown", repairCaller(this,this.down));
T.bind(document, "mousemove", repairCaller(this,this.move));
T.bind(document, "mouseup", repairCaller(this,this.stop));
}
Drag.prototype.down = function(){
//取得事件对象
var event = T.event.getEvent(arguments[0]),
target = T.event.getTarget(event);
if (target == this.moveTarget){
this.lock = false;
//在事件开始时保存各种坐标位置
this.startLeft = parseInt(this.moveTarget.style.left);
this.startTop = parseInt(this.moveTarget.style.top);
this.startClientX = event.clientX;
this.startClientY = event.clientY;
}
};
Drag.prototype.move = function(){
if(!this.lock ){
//取得事件对象
var event = T.event.getEvent(arguments[0]),
target = T.event.getTarget(event);
if(target == this.moveTarget){
//如有选择内容,清除之
//window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();
//凑数拖动范围有没超过最大限制
var realLeft = this.startLeft + event.clientX - this.startClientX, //实际的移动范围
realTop = this.startTop + event.clientY - this.startClientY,
rightLeft , rightTop; //正确的 left, top 取值
rightLeft = realLeft > this.MAX_LEFT ? this.MAX_LEFT : ( realLeft > 0 ? realLeft : 0 );
rightTop = realTop > this.MAX_TOP ? this.MAX_TOP : ( realTop > 0 ? realTop : 0 );
this.moveTarget.style.left = rightLeft + "px";
this.moveTarget.style.top = rightTop + "px";
}
else{
this.lock = true;
}
}
};
Drag.prototype.stop = function(){
this.lock = true
};