标签获取元素

1.标签获取元素

• document.getElementsByTagName();

window.onload = function () {
    var lis = document.getElementsByTagName('li');
    lis[0].style.backgroundColor = 'gold';
    lis[1].style.backgroundColor = 'gold';
}

2.循环

1. for循环

window.onload = function () {
    var olist = document.getElementById('list01');
    var ali = olist.getElementsByTagName('li');

     for(var i=0;i<8;i++){
        if(i%2 == 0){
          ali[i].style.backgroundColor = 'gold';
        }
    }
    i++;
}

2.while循环

 var i=0;
 while (i<ali.length){
  if(i%2 == 0){
      ali[i].style.backgroundColor = 'gold';
             }
       }
       i++;
       };

3.do while循环

var i = 0;
    do {
        if (i % 2 == 0) {
            ali[i].style.backgroundColor = 'gold';
        }
        i++;
    } while (i < ali.length);
}