文件大小限制问题，限制上传文件功能只能上传指定大小的文件

二话不说直接上代码：

<form id="form_uploadexcel" action="/DB/Edit/UploadExcel" method="post" enctype="multipart/form-data">
            <table width="440" border="0" cellpadding="0" cellspacing="0" class="table_none">
                <tr>
                    <td style="width: 130px" align="right"><strong>标题：<></td>
                    <td style="width:310px">
                        <input type="text" id="fileSubject" name="subject" class="easyui-validatebox" required="true" style="width: 280px" />
                        <strong style="color:#f00">*<>
                    </td>
                </tr>
                <tr>
                    <td style="width: 130px" align="right" valign="top"><strong>描述：<></td>
                    <td>
                        <textarea type="text" id="fileComment" name="comment" class="easyui-validatebox" style="width: 280px;max-width:280px; height: 90px;max-height:90px"></textarea>
                    </td>
                </tr>
                <tr>
                    <td style="width: 130px" align="right" valign="top"><strong>数据文件：<></td>
                    <td>
                        <input id="excelFile" name="excelFile" type="file" accept=".xls,.xlsx" style="width:280px" onchange="fileChange(this,1)" />
                    </td>
                </tr>
                <tr>
                    <td colspan="2" align="right" style="padding-top:20px">
                        <a href="/edit/downloadtemplate/@ViewBag.DatabaseId" class="easyui-linkbutton" data-options="iconCls:'icon-download'">下载模板</a>
                        <a href="javascript:void(0)" class="easyui-linkbutton width_80" data-options="iconCls:'icon-save'" onclick="uploadExcel()">上传</a>
                        <a href="javascript:void(0)" class="easyui-linkbutton" data-options="iconCls:'icon-save'" onclick="submitApproval()">上传并提交审核</a>
                    </td>
                </tr>
            </table>
            <input type="hidden" id="hdDatabaseId" name="databaseid" value="@ViewBag.DatabaseId" />
            <input type="hidden" id="hdRecordstatus" name="recordstatus" value="0" />
        </form>
        <input type="hidden" id="hidFileAllowType_1" value=".xls,.xlsx" />


//
function fileChange(target, filetypeid) {
    var filepath = target.value;
    if (filepath == "") {
        return false;
    }

    var fileSize = 0;
    var isIE = /msie/i.test(navigator.userAgent) && !window.opera;
    if (isIE && !target.files) {
        var fileSystem = new ActiveXObject("Scripting.FileSystemObject");
        var file = fileSystem.GetFile(filepath);
        fileSize = file.Size;
    } else {
        fileSize = target.files[0].size;
    }
    var size = fileSize / 1024;
    if (size > 61440) {
        target.value = '';
        $.messager.alert('提示', '文件大小不能大于60M！', 'warning');
        return false;
    }
    if (size <= 0) {
        target.value = '';
        $.messager.alert('提示', '文件大小不能为0M！', 'warning');
        return false;
    }
    fsize = size;
    var ss = $('#hidFileAllowType_' + filetypeid).val();
    if (ss != '') {
        var arrFileAllowType = ss.split(',');
        var fileExtension = filepath.substring(filepath.lastIndexOf('.'), filepath.length);
        var strAllowType = "";
        var isAllowType = false;
        for (var i = 0; i < arrFileAllowType.length; i++) {
            strAllowType += arrFileAllowType[i];
            if (arrFileAllowType[i].toString().toLowerCase() == fileExtension.toLowerCase()) {
                isAllowType = true;
            }
        }
        if (!isAllowType) {
            target.value = '';
            $.messager.alert("提示", "只能上传以下格式的文件：" + strAllowType);
            return false;
        }
    }
    var filename = filepath.substring(filepath.lastIndexOf('\\') + 1);
    filename = filename.substring(0, filename.lastIndexOf('.'));
    $('input[name=filename]').val(filename);
    return true;
}

web配置：

<system.web>
<httpRuntime maxRequestLength="2097151" maxQueryStringLength="2097151" maxUrlLength="2097151" executionTimeout="3600" requestValidationMode="2.0" />
</system.web>

<system.webServer>
<security>
      <requestFiltering>
        <requestLimits maxQueryString="4080" maxAllowedContentLength="2147483647" />
      </requestFiltering>
      </security>
</system.webServer>