function?animate(offset){

var?newLeft?=parseInt(list.style.left)+offset;?
var?_time?=740;//位移總時(shí)間
var?interval?=?20?//?時(shí)間間隔
var?speed?=?offset/(_time/interval);//單位時(shí)間位移量
alert(offset);
alert(speed);
alert("newLeft="?+?newLeft);
//內(nèi)部函數(shù)
var?go?=?function(){
if(?(speed<0&&parseInt(list.style.left)>newLeft)||
????????????????????(speed>0&&parseInt(list.style.left)<newLeft)?){
list.style.left?=?parseInt(list.style.left)?+speed?+"px";
setTimeout(go,interval);

}else{
list.style.left=parseInt(list.style.left)+offset+"px";
????if(newLeft>-740){
list.style.left?=?-3700+"px";
????}
????if(newLeft<-3700){
list.style.left?=?-740+"px";
????}
}
}
go();
????}

next.onclick?=?function(){
if(index==4){
index?=?0;
}else{
index?+=1;
}
//alert("test");

showButton();
animate(-740);
}
prev.onclick?=?function(){
//按鈕復(fù)位
if(index==0){
index?=?4;
}else{
index?-=?1;
}

showButton();
animate(740);
}

為什么我點(diǎn)next會(huì)跳到第三個(gè)，在沒寫go函數(shù)之前都是正常的，寫了之后有動(dòng)畫但是會(huì)直接跳兩張圖片