JS——通过标签获取元素、循环语句、数组去重

var aLi = document.getElementsByTagName(‘Li‘);
aLi[0].style.backgroundColor = ‘gold‘;

var oList = document.getElementById(‘list01‘);
var aLi = oList.getElementByTagName(‘li‘);
alert(aLi.length);

var oList = document.getElementById(‘list01‘);
var aLi = oList.getElementByTagName(‘li‘);
for(var i=0;i<aLi.length;i++){
     
     if (i%2==0){
        aLi[i].style.background = ‘gold‘;
    }
}

var aRr = [1,2,3,4,5,6,7,8,3,2,3,5,7,9,5,2,4];
var aRr = [];

for(var i=0;i<aRr.length;i++)
{
    if(aRr.indexOf(aRr[i])==i)
    {
    aRr2.push(aRr[i]);
    }
}
alert(aRr2);