简单的方法是

const myFile = document.getElementById("fileUpload").files[0]; 
            if (myFIle.size > 2097152) // 2 MiB for bytes.
            {
                alert("File size must under 2MiB!");
                return;
            }

适用于动态和静态文件元素

仅Javascript解决方案

函数validateSize(input) { const fileSize = input.files[0]。Size / 1024 / 1024;// in MiB if (fileSize > 2) { alert('文件大小超过2个MiB'); / / $(文件).val (");//使用Jquery清除 }其他{ //继续 ｝ ｝ <input onchange="validateSize(this)" type="file">

我使用这个脚本来验证文件类型和大小

var _validFilejpeg = [".jpeg", ".jpg", ".bmp", ".pdf"]; function validateForSize(oInput, minSize, maxSizejpeg) { //if there is a need of specifying any other type, just add that particular type in var _validFilejpeg if (oInput.type == "file") { var sFileName = oInput.value; if (sFileName.length > 0) { var blnValid = false; for (var j = 0; j < _validFilejpeg.length; j++) { var sCurExtension = _validFilejpeg[j]; if (sFileName.substr(sFileName.length - sCurExtension.length, sCurExtension.length) .toLowerCase() == sCurExtension.toLowerCase()) { blnValid = true; break; } } if (!blnValid) { alert("Sorry, this file is invalid, allowed extension is: " + _validFilejpeg.join(", ")); oInput.value = ""; return false; } } } fileSizeValidatejpeg(oInput, minSize, maxSizejpeg); } function fileSizeValidatejpeg(fdata, minSize, maxSizejpeg) { if (fdata.files && fdata.files[0]) { var fsize = fdata.files[0].size /1024; //The files property of an input element returns a FileList. fdata is an input element,fdata.files[0] returns a File object at the index 0. //alert(fsize) if (fsize > maxSizejpeg || fsize < minSize) { alert('This file size is: ' + fsize.toFixed(2) + "KB. Files should be in " + (minSize) + " to " + (maxSizejpeg) + " KB "); fdata.value = ""; //so that the file name is not displayed on the side of the choose file button return false; } else { console.log(""); } } } <input type="file" onchange="validateForSize(this,10,5000);" >

简单的方法是

const myFile = document.getElementById("fileUpload").files[0]; 
            if (myFIle.size > 2097152) // 2 MiB for bytes.
            {
                alert("File size must under 2MiB!");
                return;
            }

JQuery在这个线程中提供的例子是非常过时的，谷歌没有任何帮助，所以这里是我的修订:

<script type="text/javascript">
  $('#image-file').on('change', function() {
    console.log($(this)[0].files[0].name+' file size is: ' + $(this)[0].files[0].size/1024/1024 + 'Mb');
  });
</script>

我做了这样的东西:

$(" #图像文件”)。On ('change'， function() { Var numb = $(this)[0].files[0]。Size / 1024 / 1024; numb = number . tofixed (2); If (numb > 2) { alert('to big，最大值为2MiB。你的文件大小是:' + numb + ' MiB'); }其他{ alert('it okey，你的文件有' + numb + 'MiB') ｝ })； < script src = " https://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js " > < /脚本> <input type="file" id="image-file">