[jQuery] Always escape with two backslashes?

[jQuery] Always escape with two backslashes?


Hello!
I read in the documentation, the special characters like ':', we must
escape with TWO backslashes. But not always:
<script type="text/javascript">
function Nyom() {
    if ($('#pipa\\:x').is(':checked')) {
        $(':checkbox[id^=pipa\:x\:]').attr('checked','checked');
    } else {
        $(':checkbox[id^=pipa\:x\:]').removeAttr('checked');
    }
}
</script>

<input type="checkbox" id="pipa:x" onclick="Nyom()"/>


<input type="checkbox" id="pipa:x:1"/>


<input type="checkbox" id="pipa:x:2"/>


<input type="checkbox" id="pipa:x:3"/>


In form filters only works, if i used only ONE backslash to escape. Why?
Lay