Hi Andrea,
This script will block all the button click event,even if i click single or more than once.
<script type = "text/javascript">
function DisableButtons() {
    var inputs = document.getElementsByTagName("INPUT");
    for (var i in inputs) {
        if (inputs[i].type == "button" || inputs[i].type == "submit") {
            inputs[i].disabled = true;
        }
    }
}
window.onbeforeunload = DisableButtons;
</script>
 
i need to seperate the condition. i want to check the condition for single click and double click.for example ,if single click is clicked i have validated the function in client side and if double click is clicked i want to hide that button function.this script is also work, but i want to seperate the condition
 
<script type = "text/javascript">
function DisableButton() {
    document.getElementById("<%=Button1.ClientID %>").disabled = true;
}
window.onbeforeunload = DisableButton;
</script>