Javascript验证返回false仍然是页面回发？ [英] Javascript validation return false still page was postback?

问题描述

我对按钮OnClintclick事件上的文件上传控件进行了javascript验证。

javascript函数返回false仍然按钮点击事件触发...当javascript返回false时如何避免回发？



thankyou



我尝试过：



我的js代码是

i have javascript validation for file upload control on button OnClintclick event.
javascript function return false still button click event firing...how to avoid postback when javascript returns false?

thankyou

What I have tried:

My js code is

<script language="javascript" type="text/javascript">
        function checkRequiredFields() {


            var imgpath = document.getElementById('FileUpload1').value;
            if (imgpath == "") {
                alert("please select a file");
                document.file.FileUpload1.focus();
                return false;
            }
            else {
                alert("success");
            }

            var array = ['zip', 'jpg', 'jpeg', 'doc', 'docx', 'xls', 'xlsx', 'pdf', 'txt'];
            var xyz = document.getElementById("FileUpload1");
            var Extension = xyz.value.substring(xyz.value.lastIndexOf('.') + 1).toLowerCase();

            if (array.indexOf(Extension) <= -1) {
                alert("Selected file does not meet the upload criteria.");
                document.form.FileUpload1.focus();
                return false;
            }
             else {
                 alert("success");
            }

           }
       </script>

按钮控制

button control is

<asp:Button ID="CaseAttachments_btnUpload" runat="server" CssClass="FA_TextButton" Text="Upload" OnClientClick="return checkRequiredFields();" OnClick="MyButton_Click" />

推荐答案

只要javascript代码中出现错误（语法），就会发生此错误错误或运行时错误）

如果有错误（语法或运行时间），如果没有错误，它将返回 true 。

尝试检查以下内容：

放置<$ c javascript 函数的第一行中的$ c>调试器

This Error will happen whenever there is an error in the javascript code ( syntax error or run time error )
If there is an error (Syntax or run time), and if unhanded it will return as true.
Try to do check the below :
Place a debugger in the first line of your javascript function

function checkRequiredFields() {
           debugger; // debugger to stop code execution on this particular line
           var imgpath = document.getElementById('FileUpload1').value;

要调试，您可以通过启用开发人员工具来使用Chrome浏览器或IE，这可以通过

• Chrome - 按 F12 或菜单 - >工具（更多工具） - >打开开发人员工具。开发人员工具
• IE
- 按 F12





To debug you can either use Chrome browser or IE by Enabling the Developer Tools, which can be done by


• Chrome- Open the developer tools by pressing F12 or Menu->Tools (More tools) -> Developer tools
• IE
- Press F12





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