vuejs如何将线上PDF转为base64编码

只需要两个方法-下载与转换：

下载方法：

            demoDownloadPDF(url) {// if (!(/^https?:/i.test(url))) return;if (window.XMLHttpRequest) var xhr = new XMLHttpRequest(); else var xhr = new ActiveXObject("MSXML2.XMLHTTP");xhr.open('GET', url, false); //同步方式if (xhr.overrideMimeType)try {xhr.responseType = 'arraybuffer';var arrybuffer = true;} catch (err) {xhr.overrideMimeType('text/plain; charset=x-user-defined');}xhr.send(null);var data = xhr.response || xhr.responseBody;if (typeof Uint8Array !== 'undefined') {if (arrybuffer) var dataArray = new Uint8Array(data); else {var dataArray = new Uint8Array(data.length);for (var i = 0; i < dataArray.length; i++) { dataArray[i] = data.charCodeAt(i); }}} elsevar dataArray = VBS_BinaryToArray(data).toArray(); //兼容IE低版本return this.demoGetBASE64(dataArray);},

下载后将pdf转换： 

            demoGetBASE64(dataArray) {var digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";var strData = "";for (var i = 0, ii = dataArray.length; i < ii; i += 3) {if (isNaN(dataArray[i])) break;var b1 = dataArray[i] & 0xFF, b2 = dataArray[i + 1] & 0xFF, b3 = dataArray[i + 2] & 0xFF;var d1 = b1 >> 2, d2 = ((b1 & 3) << 4) | (b2 >> 4);var d3 = i + 1 < ii ? ((b2 & 0xF) << 2) | (b3 >> 6) : 64;var d4 = i + 2 < ii ? (b3 & 0x3F) : 64;strData += digits.substring(d1, d1 + 1) + digits.substring(d2, d2 + 1) + digits.substring(d3, d3 + 1) + digits.substring(d4, d4 + 1);}return strData;},