1、解析option
(1)合成column（$(target).datagrid("getColumnOption",field);）
$(_4be).children("thead").each(function(){
var opt=$.parser.parseOptions(this,[{frozen:"boolean"}]);
$(this).find("tr").each(function(){
var cols=[];
$(this).find("th").each(function(){
var th=$(this);
var col=$.extend({},$.parser.parseOptions(this,["field","align","halign","order",{sortable:"boolean",checkbox:"boolean",resizable:"boolean",fixed:"boolean"},{rowspan:"number",colspan:"number",width:"number"}]),{title:(th.html()||undefined),hidden:(th.attr("hidden")?true:undefined),formatter:(th.attr("formatter")?eval(th.attr("formatter")):undefined),styler:(th.attr("styler")?eval(th.attr("styler")):undefined),sorter:(th.attr("sorter")?eval(th.attr("sorter")):undefined)});
if(th.attr("editor")){
var s=$.trim(th.attr("editor"));
if(s.substr(0,1)=="{"){
col.editor=eval("("+s+")");
}else{
col.editor=s;
}
}
cols.push(col);
});
opt.frozen?_4c1.push(cols):_4c2.push(cols);
});
});