Try this code:
HTML
<button type='button' id = 'rbutton_'+i onclick="disable(i)">Click me</button>
function
function disable(i){
$("#rbutton_"+i).attr("disabled","disabled");
}
Other solution with jquery
$('button').click(function(){
$(this).attr("disabled","disabled");
});
Other solution with pure javascript
<button type='button' id = 'rbutton_1' onclick="disable(1)">Click me</button>
<script>
function disable(i){
document.getElementById("rbutton_"+i).setAttribute("disabled","disabled");
}
</script>