原文链接
<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta name="DEscription" contect="my code demo" /> <meta name="Author" contect="Michael@jb51.net" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta http-equiv="X-UA-Compatible" content="IE=emulateIE8"> <title>js check file size @ jb51.net</title> </head> <body> < img id="tempimg" dynsrc="" src="" style="display:none" /> <input type="file" name="file" id="fileuploade" size="40" /> <input type="button" name ="check" value="checkfilesize" οnclick="checkfile()"/> </body> <script type="text/javascript"> var maxsize = 210241024;//2M var errMsg = "上传的附件文件不能超过2M！！！"; var tipMsg = "您的浏览器暂不支持计算上传文件的大小，确保上传文件不要超过2M，建议使用IE、FireFox、Chrome浏览器。"; var browserCfg = {}; var ua = window.navigator.userAgent; if (ua.indexOf("MSIE")>=1){ browserCfg.ie = true; }else if(ua.indexOf("Firefox")>=1){ browserCfg.firefox = true; }else if(ua.indexOf("Chrome")>=1){ browserCfg.chrome = true; } function checkfile(){ try{ var obj_file = document.getElementById("fileuploade"); if(obj_file.value==""){ alert("请先选择上传文件"); return; } var filesize = 0; if(browserCfg.firefox || browserCfg.chrome ){ filesize = obj_file.files[0].size; }else if(browserCfg.ie){ var obj_img = document.getElementById(‘tempimg‘); obj_img.dynsrc=obj_file.value; filesize = obj_img.fileSize; alert(filesize); }else{ alert(tipMsg); return; } if(filesize==-1){ alert(tipMsg); return; }else if(filesize>maxsize){ alert(errMsg); return; }else{ alert("文件大小符合要求");alert(filesize); return; } }catch(e){ alert(e); } } </script></html>
js判断文件大小利用img 的 dynsrc，兼容IE10 及以上
原文：https://www.cnblogs.com/sunny3158/p/12181852.html