求大神帮忙 第二句是别人打给我参考的
2条回答 默认 最新
- cocotsau 2016-04-21 14:08关注
看下代码,真挺麻烦
<!doctype html> <html> <head> <meta charset="utf-8"> <title>无标题文档</title> <style> li {float:left; height:50px; width:50px; background:#ccc; list-style:none; margin-left:5px;} li.curr {background:red;} </style> <script type='text/javascript'> function hasClass(obj, sCls){ return obj.className.match(new RegExp("\\b"+sCls+"\\b", "i")); } function addClass(obj, sCls){ var blank=(obj.className!="")?" ":""; if(!hasClass(obj, sCls))obj.className+=blank+sCls; } function removeClass(obj, sCls){ var re=new RegExp("(\\s|^)"+sCls+"(\\s|$)", "i"); if(hasClass(obj, sCls))obj.className=obj.className.replace(re, ""); } function prevAll(arr,sCls){ var index=0; for(var i=0;i<arr.length;i++){ if(hasClass(arr[i],sCls))index=i; } return index; } window.onload=function(){ var aLi=document.getElementsByTagName('li'), index; var movePrev = function (){ index=prevAll(aLi,'curr'); if(index==0){//可循环移动 removeClass(aLi[index],'curr'); addClass(aLi[aLi.length-1],'curr'); index = aLi.length-1; console.log(index); }else{ removeClass(aLi[index],'curr'); addClass(aLi[index-1],'curr'); index--; console.log(index); } } var moveNext = function (){ index=prevAll(aLi,'curr'); if(index==aLi.length-1){//可循环移动 removeClass(aLi[aLi.length-1],'curr'); addClass(aLi[0],'curr'); index = 0; }else{ removeClass(aLi[index],'curr'); addClass(aLi[index+1],'curr'); index++; } } document.onkeydown=function(e){ var e = e || event, code = e.keyCode || e.which; code==38 && movePrev(); code==40 && moveNext(); } }; </script> </head> <body> <ul> <li class='curr'></li> <li></li> <li></li> <li></li> <li></li> <li></li> </ul> </body> </html>
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