How to change charting.fieldColors through JS

Hi all, Setting "charting.fieldColors" in XML always works, but it failed when I try to change this value through js. My code is like this: var chartview = mvc.Components.get("chartid"); chartview.settings.set("charting.fieldColors",'{"sth":0x65a637}'); // tried call network.render(); already Is there any way to change fieldColors through JS? Thanks.