js-奇技淫巧

• 执行浏览器复制命令

注：只能复制文本框内的文字（ input / textarea ）

function jsCopy(){ 
    var e = document.getElementById("content");//对象是content 
    e.select(); //选择对象 
    document.execCommand("Copy"); //执行浏览器复制命令
    alert("已复制好，可贴粘。"); 
} 

• 文件上传进度条 - 原生ajax & 跨域问题
• 用JavaScript将canvas保存成图片格式

// Converts canvas to an image
function convertCanvasToImage(canvas) {
    var image = new Image();
    image.src = canvas.toDataURL("image/png");
    return image;
}

• 低级浏览器升级提示

<!--IE7以下极低级浏览器升级提示-->
<!--[if lte IE 7]>
　　<script>window.location.href='http://cdn.dmeng.net/upgrade-your-browser.html?referrer='+location.href;</script>
<![endif]-->

• 判断浏览器类型

// 判断浏览器类型
function getBrowser() {
    let ua = window.navigator.userAgent;
    let isIE = window.ActiveXObject != undefined && ua.indexOf("MSIE") != -1;
    let isEdge = ua.indexOf("Trident") != -1;
    let isFirefox = ua.indexOf("Firefox") != -1;
    let isOpera = window.opr != undefined;
    let isChrome = ua.indexOf("Chrome") && window.chrome;
    let isSafari = ua.indexOf("Safari") != -1 && ua.indexOf("Version") != -1;
    if (isIE) {
      return "IE";
    } else if (isFirefox) {
      return "Firefox";
    } else if (isOpera) {
      return "Opera";
    } else if (isChrome) {
      return "Chrome";
    } else if (isSafari) {
      return "Safari";
    } else if (isEdge) {
      return "isEdge";
    } else {
      return "Unkown";
    }
}
//判断是移动端还是pc
function isMobileOrPC(){
    let map = {
        phone:'phone',
        pad:'pad',
        pod:'pod',
        iPhone:'iPhone',
        iPod:'iPod',
        ios:'ios',
        iPad:'iPad',
        Android:'Android',
        Mobile:'Mobile',
        BlackBerry:'BlackBerry',
        IEMobile:'IEMobile',
        MQQBrowser:'MQQBrowser',
        JUC:'JUC',
        Fennec:'Fennec',
        wOSBrowser:'wOSBrowser',
        BrowserNG:'BrowserNG',
        WebOS:'WebOS',
        Symbian:'Symbian',
        "Windows Phone":"Windows Phone"
    }
    let reg = new RegExp(Object.values(map).join('|'),'i')
    if ((navigator.userAgent.match(reg))) {
        return 'mobile';
    }
    return 'pc';
}
  
export default {
    getBrowser,
    isMobileOrPC
}

• 禁止、恢复H5页面滑动

//禁止H5页面滑动
document.body.style.overflow = 'hidden';
function _preventDefault(e) {
    e.preventDefault();
}
window.addEventListener('touchmove', _preventDefault);

//恢复滑动
document.body.style.overflow = 'auto';
window.removeEventListener('touchmove', _preventDefault);