jQuery-File-Upload如何限制上传文件的大小

add: function(e, data) {
         var uploadErrors = [];
         var acceptFileTypes = /^image\/(gif|jpe?g|png)$/i;
//文件类型判断
         if(data.originalFiles[0]['type'].length && !acceptFileTypes.test(data.originalFiles[0]['type'])) {
             uploadErrors.push('Not an accepted file type');
         }
//文件大小判断
         if(data.originalFiles[0]['size'].length && data.originalFiles[0]['size'] > 5000000) {
             uploadErrors.push('Filesize is too big');
         }
         if(uploadErrors.length > 0) {
             alert(uploadErrors.join("\n"));
         } else {
             data.submit();
         }
 }