Below is a pretty simple trick to convert PHP array to JavaScript array:
$array = array("one","two","three");
JS below:
// Use PHP tags for json_encode()
var js_json = json_encode($array);
var js_json_string = JSON.stringify(js_json);
var js_json_array = JSON.parse(js_json_string);
alert(js_json_array.length);
It works like a charm.