jQuery Grid Plugin - jqGrid

hello!

if code like this

<div width="20%">here is an area and width is 20%</div>

<div width="20%">here is a jqgrid and width is 20%，column must be auto fit</div>

<div width="60%">here is an area and width is 60%</div>

how to set  jqgrid's width=100% to fit the div(<div width="20%">),so when the 

window resized，the 
20%,20%,60% will work ok！