Padding in header cell

Is there a way to modify this css code via JavaScript?

div.gridbox_dhx_skyblue table.hdr td div.hdrcell{
	padding-left:10px;
	width:auto;
}

I want to make it 3px but don’t want to lose it every upgrade.

You can access to the grid header with following code:

var header=gridObj.hdr;