參考:http://www.tianshan277.com/563.html
效果:

html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>js加載</title>
<script>
function errorload(elem) { //cdn錯誤
if (elem.getAttribute('data-errorTimes') == 1) {
elem.onerror = null; // 執行完onerror事件后,置onerror=null 來清除onerror事件。
return;
}
elem.setAttribute('data-errorTimes', 1);
var _src = elem.getAttribute('data-localSrc');
loadScript(_src, elem);
}
function loadScript(_src, prevEl) { //引入本地js
var _el = document.createElement('script');
_el.src = _src;
if (prevEl) {
prevEl.parentNode.insertBefore(_el, prevEl.nextSibling);
} else {
document.body.appendChild(_el);
}
}
</script>
</head>
<body>
<p>產品一</p>
<p>產品二</p>
<p>產品三</p>
<p>產品四</p>
<p>產品五</p>
<script data-localSrc="js/jquery.js" type="text/javascript" src="https://cdn.bootcss.com/jquery/1.8.2/jquery.min.js"
onerror="errorload(this);"></script>
//此cdn是正確版,測試時可修改為錯誤版再測試
</body>
</html>
