]
Look at the key js code:
The code is as follows:
var $ = function (d){
typeof d == "string" &&(d = document.getElementById(d));
return $.fn.call(d);
};
$.fn = function (){
this.addEvent = function (sEventType,fnHandler){
if (this.addEventListener) {this.addEventListener(sEventType, fnHandler, false);}
else if (this.attachEvent) {this.attachEvent("on " sEventType, fnHandler);}
else {this["on" sEventType] = fnHandler;}
}
this.removeEvent = function (sEventType,fnHandler){
if (this.removeEventListener) {this.removeEventListener(sEventType, fnHandler, false);}
else if (this.detachEvent) {this.detachEvent("on" sEventType, fnHandler);}
else { this["on" sEventType] = null;}
}
return this;
};
var Class = {create: function() {return function() { this.initialize.apply(this, arguments); }}} ;
var Bind = function (obj,fun,arr){return function() {return fun.apply(obj,arr);}}
var Marquee = Class.create();
Marquee. prototype = {
initialize: function(id,name,out,speed) {
this.name = name;
this.box = $(id);
this.out = 3;/ /Scroll interval time, unit second
this.speed = speed;
this.d = 1;
this.box.style.position = "relative";
this.box.scrollTop = 0 ;
var _li = this.box.firstChild;
while(typeof(_li.tagName)=="undefined")_li = _li.nextSibling;
this.lis = this.box.getElementsByTagName(_li .tagName);
this.len = this.lis.length;
for(var i=0;ivar __li = document.createElement(_li. tagName);
__li.innerHTML = this.lis[i].innerHTML;
this.box.appendChild(__li);//cloneNode
if(this.lis[i].offsetTop>=this .box.offsetHeight)break;
}
this.Start();
this.box.addEvent("mouseover",Bind(this,function(){clearTimeout(this.timeout);}, []));
this.box.addEvent("mouseout",Bind(this,this.Start,[]));
},
Start:function (){
clearTimeout( this.timeout);
this.timeout = setTimeout(this.name ".Up()",this.out*1000)
},
Up:function(){
clearInterval(this .interval);
this.interval = setInterval(this.name ".Fun()",10);
},
Fun:function (){
this.box.scrollTop =this .speed;
if(this.lis[this.d].offsetTop <= this.box.scrollTop){
clearInterval(this.interval);
this.box.scrollTop = this.lis [this.d].offsetTop;
this.Start();
this.d ;
}
if(this.d >= this.len 1){
this. d = 1;
this.box.scrollTop = 0;
}
}
};
$(window).addEvent("load",function (){
marquee = new Marquee("msg_weibo","marquee",1,2);
});
The implementation idea is the same as the previous text scrolling, which is to fill the current container first. Then scroll up through scrollTop, but the distance of each scroll is not fixed, it is the height of the current scroll message. Due to the difference between scrollTop (the height of scrolling out of the current visible area) and offsetTop (the distance from the top of the parent node, often used to obtain the coordinate position of an element on the page), through if(this.lis[this.d].offsetTop <= this.box.scrollTop) to determine whether the last message has been scrolled and needs to be paused.
I think the highlight is the way $ is written. Usually obj||document.getElementById('objId') is removed from Prototype. In addition, he also binds some methods to obj. Is its role similar to the prototype's method of extending String, Array and other objects? This can be learned from.
In addition, when filling the container during initialization, use document.createElement->assign innerHTML->appendChild to do it. I think it is not as good as directly cloneNode(true)->appendChild. If it is wrong, please correct me.
The main thing is to fill in the gaps this month, haha.
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![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
