百度搜索了很多，但是始终没有完成需求，只是在ios浏览器上下载个pdf，麻烦的要死，希望华为或者小米的生态能早点做起来。
<body><button id="download">down</button></body><script>var url ="https://xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"var down = document.getElementById(\'download\')down.onclick = function () {var ua = navigator.userAgent.toLowerCase();//判断是不是在iPhone的Safair浏览器打开的本页面if (ua.indexOf(\'applewebkit\') > -1 && ua.indexOf(\'mobile\') > -1 && ua.indexOf(\'safari\') > -1 &&ua.indexOf(\'linux\') === -1 && ua.indexOf(\'android\') === -1 && ua.indexOf(\'chrome\') === -1 &&ua.indexOf(\'ios\') === -1 && ua.indexOf(\'browser\') === -1) {// document.write("【是 Safari】");down1(url)} else {// document.write("【不是 Safari】");down2(url)}}function down1(url) {var src = urlvar iframe = document.createElement(\'iframe\');iframe.style.display = \'none\';iframe.src = "javascript: \'<script>location.href=\"" + src + "\"<\/script>\'";document.getElementsByTagName(\'body\')[0].appendChild(iframe);}function down2(url) {window.open(url)}</script>