Disable LinkButton on PostBack using JavaScript in ASP.Net

Hi Waghmare,

Refer below sample.

HTML

<asp:Button ID="btnSubmit" runat="server" OnClick="btnSubmit_Click" Font-Bold="true"
    Text="Submit" ToolTip="Submit" OnClientClick="disableBtn(this.id, 'Submitting...')"
    UseSubmitBehavior="false" CssClass="btn btn-block btn-success" />
<br />
<asp:LinkButton ID="btnSave" runat="server" OnClick="btnSave_Click" class="btn" ToolTip="Delete"
    OnClientClick="disableBtn(this.id, '')" UseSubmitBehavior="false"><i class="fa fa-trash"></i> Trash</asp:LinkButton>
<link rel="stylesheet" media="screen" href='https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/css/bootstrap.min.css' />
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />
<style type="text/css">
    .btn {
        background-color: DodgerBlue;
        border: none;
        color: white;
        padding: 12px 16px;
        font-size: 16px;
        cursor: pointer;
    }

        .btn:hover {
            background-color: #4CAF50;
        }
</style>
<script type="text/javascript">
    function disableBtn(btnID, newText) {
        Page_IsValid = null;

        if (typeof (Page_ClientValidate) == 'function') {
            Page_ClientValidate();
        }
        var btn = document.getElementById(btnID);
        var isValidationOk = Page_IsValid;

        if (isValidationOk !== null) {
            if (isValidationOk) {
                btn.disabled = true;
                btn.value = newText;
            } else {
                btn.disabled = false;
            }
        } else {
            btn.disabled = true;
            btn.value = newText;
        }
    }
</script>

Code

protected void btnSubmit_Click(object sender, EventArgs e)
{
   
}

protected void btnSave_Click(object sender, EventArgs e)
{
    
}

Screenshot