Native javascript implementation of seamless scrolling example_javascript skills

// Write In anonymous functions, prevent global variable pollution
(function(){
var target = document.getElementById('marScroll'),
oUl = target.getElementsByTagName('ul')[0];
// If the content is small, exit this function directly
if(oUl.offsetHeight})();

target.innerHTML = target.innerHTML;
/* When judging that the distance of each scroll is equal to the height of the first ul, set scrollTop to 0, and then Such a loop operation results in endless scrolling
--------------------------------------------- -------------------------------------------------- ----*/
// Extract the functional function for easy calling
var fn = function(){
if(target.scrollTop == oUl_h){
target.scrollTop = 0;
}else{
target.scrollTop;
}
}
// setInterval loop
var timer = setInterval(function(){
fn();
},30);

// hover
target.onmouseover = function(){
clearTimeout(timer);
}
target.onmouseout = function(){
timer = setInterval(function(){
fn();
},30);
}

//Written in an anonymous function to prevent global variable pollution
(function(){
var target = document.getElementById('marScroll'),
oUl = target.getElementsByTagName('ul')[0],
oUl_h = oUl.offsetHeight;
// If the content is small, exit this function directly
if(oUl_h
target.innerHTML = target.innerHTML;

/* Determine the size of each scroll When the distance is equal to the height of the first ul, set scrollTop to 0, and then such a loop operation will scroll continuously
----------------------- -------------------------------------------------- --------------------*/
// Extract the function function to facilitate calling
var fn = function(){
if (target.scrollTop == oUl_h){
target.scrollTop = 0;
}else{
target.scrollTop;
}
}
// setInterval loop
var timer = setInterval(function(){
fn();
},30);
// hover
target.onmouseover = function(){
clearTimeout(timer);
}
target.onmouseout = function(){
timer = setInterval(function(){
fn();
},30);
}
})() ;

function GyMarquee(opt){
this.opt = opt;
if(!document.getElementById(this.opt.targetID )) return;
this.target = document.getElementById(this.opt.targetID);
this.dir = this.opt.dir == 'crosswise'?'crosswise':'vertical';
this.effect = this.opt.effect == 'scroll'?'scroll':'marque';
this.scrollHeight = this.opt.scrollHeight;
this.init();
}
GyMarquee.prototype = {
marquee:function(){
var _that = this,
direction = 'scrollTop',
judge = this.target.scrollHeight,
timer = null;
if(this.dir == 'crosswise'){
direction = 'scrollLeft';
judge = this.itemLen*this.opt.itemWidth;
this.targetChild.style. width = this.itemLen*this.opt.itemWidth*2 'px';
}
var doFn = function(){
if(_that.target[direction] == judge){
_that.target[direction] = 0;
}
_that.target[direction] ;
}
timer = setInterval(function(){
doFn();
}, 38);
this.target.onmouseover = function(){
if(timer) clearTimeout(timer);
}
this.target.onmouseout = function(){
timer = setInterval(function(){
doFn();
},38);
}
},
scrollDo:function(){
var can = true,
_that = this;
this.target.onmouseover=function(){can=false};
this.target.onmouseout=function(){can=true};
new function (){
var stop=_that.target.scrollTop%_that.scrollHeight==0&&!can;
if(!stop)_that.target.scrollTop==parseInt(_that.target.scrollHeight/2)?_that.target.scrollTop =0:_that.target.scrollTop;
setTimeout(arguments.callee,_that.target.scrollTop%_that.scrollHeight?20:2500);
};
},
getByClassName:function( className,parent){
var elem = [],
node = parent != undefined&&parent.nodeType==1?parent.getElementsByTagName('*'):document.getElementsByTagName('*'),
p = new RegExp("(^|\s)" className "(\s|$)");
for(var n=0,i=node.length;n if(p.test(node[n].className)){
elem.push(node[n]);
}
}
return elem;
},
init:function(){
var val = 0;
if(this.dir =='crosswise'&&this.effect=='marque'&&this.opt.itemName!=''){
this .itemLen = this.target.getElementsByTagName(this.opt.itemName).length;
val = this.itemLen*this.opt.itemWidth;
}else{
val = this.target.scrollHeight;
}
var holderHTML = this.target.innerHTML;
this.target.innerHTML = '

' holderHTML '

';
this .targetChild = this.getByClassName('J_scrollInner',this.target)[0];
var attr = this.dir == 'vertical'?'offsetHeight':'offsetWidth';
if(val>this .target[attr]){
if(this.effect == 'scroll'){
this.scrollDo();
}else{
this.marquee();
}
this.targetChild.innerHTML = this.targetChild.innerHTML;
}
}
}