Issue With Checkbox

I am trying to get the value from the Kendoui Checkbox but without success so far.

<input type="checkbox" id="telephonyeq1" name="telephonychk[]" class="k-checkbox telephonycb">

The script

<script>
    if($('#telephonyeq1').is(":checked"))
        {
        var telephonycb = "true"
        }
        else {
        var telephonycb = "false"
        }
</script>

when i am POST the data through AJAX i am always receiving value as "False", even if it's checked or unchecked.

Telephony: false 

Can you advice me please?