JavaScript列表遍历为什么返回undefined？？？

var youjunList["bk_polysemy","31713","34689","lego_tpl","sigma_celebrity_rela","www_jingyan_normal","www_normal","10"]; for(var j = 0 , youjunListLen = youjunList.length; j < youjunList; j++) { console.log(youjunList[j]); }

  aaa() {

    var dc=["bk_polysemy", "31713", "34689", "lego_tpl", "sigma_celebrity_rela", "www_jingyan_normal", "www_normal", "10"];

    for (let j = 0;  j <  dc.length; j++) {

      console.log(dc[j]);

    }

  },

<script>
var youjunList=["bk_polysemy","31713","34689","lego_tpl","sigma_celebrity_rela","www_jingyan_normal","www_normal","10"];
     for(var j = 0 , youjunListLen = youjunList.length; j < youjunListLen; j++){
      console.log(youjunList[j]);
     }
</script>

1.var 变量的时候少了一个等于号

2.for循环时j小于的应该是你youjunList长度赋值得到的youjunListLen，或者可以直接写成j<youjunList.length

 遍历直接用for...in循环就好了

for(var i in dc){
console.log(dc[i]);
}