第一种：
jqGrid随窗口大小变化自适应宽度
$(function(){
$(window).resize(function(){
$("#listId").setGridWidth($(window).width());
});
});
第二种：
window.onresize = function _doResize() {
var ss = pageSize();
$("#listId").jqGrid('setGridWidth', ss.WinW-10).jqGrid('setGridHeight', ss.WinH-200);
}
function pageSize() {
var winW, winH;
if(window.innerHeight) {// all except IE
winW = window.innerWidth;
winH = window.innerHeight;
} else if (document.documentElement && document.documentElement.clientHeight) {// IE 6 Strict Mode
winW = document.documentElement.clientWidth;
winH = document.documentElement.clientHeight;
} else if (document.body) { // other
winW = document.body.clientWidth;
winH = document.body.clientHeight;
} // for small pages with total size less then the viewport
return {WinW:winW, WinH:winH};
}