accept可限制上传所选文件是什么类型
<input type="file" style=‘display: none;‘ id="image_upload" accept="image/jpeg, image/png, image/jpg" >
1 var fileInput = document.getElementById("image_upload"); 2 ????//选择文件 3 ????fileInput.addEventListener(‘change‘,function(){ 4 ????????//如果未传入文件则中断 5 ????????if(fileInput.files[0] == undefined){ 6 ????????????return; 7 ????????} 8 ?????????9 ????????var file = fileInput.files[0];10 ????????11 ????????//FileReader可直接将上传文件转化为二进制流12 ????????var reader = new FileReader(); ?13 ????????reader.readAsDataURL(file);//转化二进制流，异步方法14 ????????reader.onload = function(){//完成后this.result为二进制流15 ????????????console.log(this.result);16 ????????????17 ????????????//页面显示文件名18 ????????????$("#name").html(file.name);19 ????????????20 ????????????var base64Str = this.result;21 ????????????var startNum = base64Str.indexOf("base64,");22 ????????????startNum = startNum*1 + 7;23 ????????????//去除前部格式信息（如果有需求）24 ????????????var baseStr = base64Str.slice(startNum);25 ????????????26 ????????????//临时存储二进制流27 ????????????$("#tempName").val(baseStr);
28
29 ? }
30 })JS 上传图片转换成二进制流base64
原文地址：https://www.cnblogs.com/sky2blue/p/10522075.html