Two asp:upload required validate attest in one at time in btn click ?

To validate that at least one file uploader is required in a web form using JavaScript, check if any of the file input elements have a selected file. If none do, show an error message. You can use the input[type="file"]:valid selector in conjunction with the :invalid pseudo-class to implement this validation.

To validate that at least one file uploader is required in a web form using JavaScript, you can use the following approach:

1. Add a validation function triggered on form submission.
2. Inside the function, iterate through all file input elements.
3. Check if any of them have a selected file. If at least one does, the validation passes.
4. If none of the file inputs have a selected file, show an error message and prevent form submission.

Add your asp:FileUpload controls to your ASP.NET page: 

Add a validation function and a hidden field to store the validation result in your ASP.NET page:

Add a button on your ASP.NET page and attach the validateFileUpload function to its onclick event:

protected void btnSubmit_Click(object sender, EventArgs e)
{
    if (hdnUploadRequired.Value == "true")
    {
        // At least one file upload was selected; proceed with your logic here
    }
    else
    {
        // No file uploads were selected; show an error message or take appropriate action
    }
}