Combotree in javascript (jquery)

I'm looking for a component which enable display tree in combo (select).
Something like that: http://www.jeasyui.com/demo/index.php

But this component doesn't allow import JSON directly, only from file.

It works in that way:

$('#cc').combotree({  
         url:'tree_data.json'  
     });
 

I need (pseudocode):

$('#cc').combotree({  
         data:'[{"id":1,"text":"City","children":[{"id":11,"text":"Wyoming","children":[{"id":111,"text":"Albin"}]}]}]' 
     });
 

Or (pseudocode):

$('#cc').combotree({  
         data:'<?php $json_string; ?>'  
     });
 

Is it possible? Or maybe do you know any components which enable to do that?

Regards,
Chris

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