creating a javasscript variable for each element in a simple php array

Question

I have a simple php array, something like $arr = ('volvo','mazda','bmw'..) How can I create js variables that all have the name based on the elements in the PHP array?

(I am asking for a method that would give me equivalant to hard coding this as

var volvo_js=0;
var mazda_js=0;
var bmv_js=0;

.. )

This naive attempt did not work:

var arr =<?php echo json_encode($arr);?>;

$.each(arr, function( index, value ){

var $(value+"_js")=0;

});