undefined variable error javascript with php

you want to do something simple like passing variable like this

<?php 
 $variable_name = "some value";
var some_var = <?=$variable_name" ?>;

but it didn’t work
Here is the solved version…
Very simple than you thought

<pre>
 $variable_name = "some value";
var some_var = "<?=$variable_name" ?>";
</pre>

yup, just quote it from left and right so that it wont be considered as string not JS variable. If the value in variable is number, there would not be any problem