纯代码给WordPress网站添加弹窗广告功能

var popup = document.getElementById('qgg_popup');
var popup_box = document.querySelector('.qgg_popup_box');
var popup_close = document.querySelector('.qgg_popup_close');
// 窗口加载时弹出
window.onload = function() {
    popup.style.display = "block";
}
// 点击窗体其他位置时关闭
window.onclick = function(event) {
    if (event.target == popup) {
        popup.style.display = "none";
    }
}
popup_box.onclick = function() {
    popup.style.display = "none";
}
// 点击关闭按钮时关闭
popup_close.onclick = function() {
    popup.style.display = "none";
}

/* 弹窗广告css 2018-8-29 */
html, body{ margin:0; height:100%; }
#qgg_popup{
    position: fixed;
    top: 0; left: 0;
    display: none;
    width: 100%;
    height: 100%;
    margin: auto;
    background: rgba(36, 36, 36, 0.8);
}

.qgg_popup_box { 
    z-index: 10; 
    position: absolute;
    top: 0; left: 0; bottom: 0; right: 0;
    width: 280px;
    height: 396px;
    margin: auto;
    text-align: center; 
} 
.qgg_popup_close{
    position: relative;
    width: 36px;
    height: 36px;
    background: #fff;
    color: #999;
    float: right;
    font-size: 24px;
    text-align: center;
    border-radius: 50%;
    line-height: 36px;
    font-weight: bold;
}

.qgg_popup_close:hover,
.qgg_popup_close:focus {
    color: red;
    cursor: pointer;
}

.qgg_popup_img{
    position:relative;
    top: 36px;
    left: 0px;
    width:240px;
    height:360px;
    border-radius: 15px;
}
@media (max-width: 640px){
    .qgg_popup_close{ display: none; }
}

<!-- 弹窗广告 -->
<div id="qgg_popup">
    <div class="qgg_popup_box">
        <span class="qgg_popup_close">&times;</span>
        <img class="qgg_popup_img" src="./1.png">
    </div>
</div>