Show Hide HTML DIV using JavaScript from code behind using C# and VB.Net in ASP.Net

Hi nauna,

Check this example. Now please take its reference and correct your code.

HTML

<asp:Button ID="btnToggle" Text="Toggle" runat="server" OnClick="OnToggle" />
<hr />
<div id="dvDetails">
    DV Details
</div>
<asp:HiddenField ID="hfDetails" runat="server" />
<script type="text/javascript">
    function ShowHideDiv() {
        var divDetails = document.getElementById('dvDetails');
        var hfDetails = document.getElementById('hfDetails');
        if (hfDetails.value == "1" || hfDetails.value == "") {
            divDetails.style.display = "none";
            hfDetails.value = "0";
        } else {
            divDetails.style.display = "block";
            hfDetails.value = "1";
        }
    }
</script>

Code

C#

protected void OnToggle(object sender, EventArgs e)
{
    ScriptManager.RegisterStartupScript(this, this.GetType(), "ShowHideDiv", "ShowHideDiv()", true);
}

VB.Net

Protected Sub OnToggle(ByVal sender As Object, ByVal e As EventArgs)
    ScriptManager.RegisterStartupScript(Me, Me.GetType(), "ShowHideDiv", "ShowHideDiv()", True)
End Sub

Screenshot