Prevent double submission of forms |二重送信防止

<!-- 送信ボタン2度押し防止策 -->
<script type="text/javascript">
var isSave = false;
function check(){
if (!isSave) {
isSave = true;
return true;
}
return false;
}

<apex:commandButton action="{!test}" value="Refresh" onclick="return check();"/>

https://developer.salesforce.com/forums?id=906F000000095yxIAA
http://salesforce.stackexchange.com/questions/7729/disable-commandbutton-after-first-click-to-prevent-double-submission