ASP.NET/JavaScript - “Return False” Not Preventing Postback

Question

I have a problem in my web application, even the validation is false the button click event will be fired.

here my design page:

<asp:TextBox ID="txtAddJournal" runat="server" />
<asp:Button ID="btnUpload" runat="server" Text="Upload" OnClientClick="Validate();" OnClick="btnUpload_click"/>

here my validation function:

function Validate() {
    var Journal = document.getElementById('<%= txtAddJournal.ClientID %>').value.trim();
    // alert(Journal);
    if (Journal == "" || Journal == null) {
        alert("Enter the Journal name");
        return false;
    }
}

and my code behind

protected void btnUpload_click(object sender, EventArgs e)
{
    check.Value = "1";
    Page.ClientScript.RegisterStartupScript(this.GetType(), "CallMyFunction", "Load_functions()", true);        

    //txtAddJournal.Attributes.Add("Style", "display:block");
    //btnUpload.Attributes.Add("Style", "display:block");
    if (fileuploader.HasFile)
    {
        try
        {
            string Filename = Path.GetFileName(fileuploader.FileName);
            //fileuploader.SaveAs(Server.MapPath("~/") + Filename);
            // fileuploader.SaveAs(Server.MapPath("D:\\Req Sep16\\") + Filename);
            OleDbConnection myconnectionini = default(OleDbConnection);
            OleDbDataAdapter mycommandini = default(OleDbDataAdapter);
            if (fileuploader.PostedFile.FileName.EndsWith(".xls") == false & fileuploader.PostedFile.FileName.EndsWith(".xlsx") == false)
            {
                // lbl_Error.Text = "Upload only excel format";
                Response.Write(@"<script language='javascript'>alert('Upload only excel format');</script>");
                return;
            }
            else
            {
                gvDetails.DataSource = null;

                string pathToSave = HttpContext.Current.Server.MapPath("~/UploadFiles/") + fileuploader.FileName;
                fileuploader.PostedFile.SaveAs(pathToSave);
                //strFilePath = "D:\\Files\\" + fileuploader.FileName;

                string constrini = "provider=Microsoft.Jet.OLEDB.4.0;data source=" + pathToSave + ";Extended Properties=Excel 8.0;";
                DataSet ds = new DataSet();
                // DataTable dt = new DataTable();        
                myconnectionini = new OleDbConnection(constrini);
                mycommandini = new OleDbDataAdapter("select * from [Sheet1$]", myconnectionini);
                ds = new DataSet();
                mycommandini.Fill(ds);

                gvDetails.DataSource = ds.Tables[0];
                gvDetails.DataBind();
            }
        }
        catch (Exception ex)
        {
            string msg = ex.Message;
        }
    }
}

please suggest me to get a solution

Tim Schmelter · Accepted Answer · 2014-11-05 12:13:16Z

7

You also have to return false from OnClientClick:

OnClientClick="return Validate();"

function Validate() {
    var Journal = document.getElementById('<%= txtAddJournal.ClientID %>').value.trim();
   // alert(Journal);
    if (Journal == "" || Journal == null) {
        alert("Enter the Journal name");
        return false;
    }
    return true;
}

answered Nov 5, 2014 at 12:13

Tim Schmelter

462k79 gold badges721 silver badges981 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

ASP.NET/JavaScript - “Return False” Not Preventing Postback

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related