js 算法面试常见的问题

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<tab切换><!doctype html><html lang="en"> <head>  <meta charset="UTF-8">  <meta name="Generator" content="EditPlus®">  <title>Document</title>  <style type="text/css">  *{  margin:0;  padding: 0;  text-align:center;  }  .box{  width:800px;  height:300px;  border:1px solid #000000;  margin:0 auto;  }  .box ul{  height:100px;  width:100%;  display: flex;  }  .box ul li{  flex:1;  height:100%;  list-style: none;  font:20px/100px "";    }  .box ul li:hover{  background:#006400 ;  }  #photo{  width:100%;  height:200px;  display: flex;  }  #photo span{  flex:1;  }  </style> </head> <script type="text/javascript"> window.onload=function(){var _li=document.querySelectorAll("#ul li");//得到所有livar _photo=document.querySelectorAll("#photo span"); for (i=0;i<_li.length;i++){_li[i].index=i;_li[i].onmouseover=function(){for(i=0;i<_photo.length;i++){_photo[i].style.display = "none";}_photo[this.index].style.display = "block";}}} </script> <body> <div class = "box"><ul id="ul"><li>red</li><li>yellow</li><li>black</li><li>pink</li></ul><div id="photo"><span style = "background:red">1</span><span style = "background:yellow">2</span><span style = "background:black">3</span><span style = "background:pink">4</span></div></div> </body></html>

//数组去重

   var arr = [1,2,3,4,1,2];            function removeArr(arr){                var tmp = {};                var newArr = [];                for(i=0;i < arr.length; i++){                    if(!tmp[arr[i]]){                        tmp[arr[i]] = true;                        newArr.push(arr[i]);                    }                }                console.log(newArr);            }            //removeArr(arr);

//异步

for(var i = 0; i <= 3; i++){                setTimeout(function(){                    //console.log(i)//4444                },0)            }            for(var i = 0; i <= 3; i++){//                setTimeout(//                    console.log(i)//0123//                ,0)            }

//变量提升

   var s = 1;            function a (){                //console.log(s);//undefined                var s = 3;                //console.log(s++);//3            }            function b(){                //console.log(s);//1                s++;                //console.log(++s);//3            }            if(100 < 0 <0){                a();            }else{                b();            }            if(0 < 1 < (0+4)){                a();            }else{                b();            }

//冒泡排序

 var bubbleArr = [1,3,4,2,6];            function bubble (bubbleArr){                var tmp;                for(var i = 0,j = bubbleArr.length; i < j; i++){                    for(var k = 1; k < i; k++){                        if(bubbleArr[i] < bubbleArr[k]){                            tmp = bubbleArr[i];                            bubbleArr[i] = bubbleArr[k];                            bubbleArr[k] = tmp;                        }                    }                }                console.log(bubbleArr);            }

//字符串倒序

  var str = "1,3,4,5,6,7,8";            console.log(str.split(",").reverse().join(" "))            var string = str.split("").reverse().join('');            str.split("")//把字符串分割成数组，如果无参数则每个元素都会被分割，有参数以参数分割            console.log(string);

《未完待续》

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js 算法 面试常见的问题

js 算法面试常见的问题