上传前检查文件大小

您可以使用

file reader

HTML5

中的Javascript读取本地文件：http

//www.html5rocks.com/en/tutorials/file/dndfiles/

    function handleFileSelect(evt) {      var files = evt.target.files; // FileList object      // files is a FileList of File objects. List some properties.      var output = [];      for (var i = 0, f; f = files[i]; i++) {        console.log(f.size);              }    }    document.getElementById('files').addEventListener('change', handleFileSelect, false);