window.addEventListener('load', function() {
//获取元素
var arrow_l = document.querySelector('.arrow_l');
var arrow_r = document.querySelector('.arrow_r');
var focus = document.querySelector('.focus');
focus.addEventListener('mouseenter', function() {
arrow_l.style.display = 'block';
arrow_r.style.display = 'block';
})
focus.addEventListener('mouseleave', function() {
arrow_l.style.display = 'none';
arrow_r.style.display = 'none';
})
})
封装的js调用不了css属性是因为什么原因
.arrow_l {
display:none;
position: absolute;
top: 205px;
left: 0;
width: 25px;
height: 42px;
background-color: rgba(0, 0, 0, .3);
color: #fff;
font-size: 28px;
}