datagrid 的标题的内容不对应整齐

$(document).ready(function(){

var column = "[["+
    "{'title':'工号','field':'grantorCode','sortable':'true','hidden':'true','width':fixWidth(0)},"+
    "{'title':'外出告知人','field':'grantor','sortable':'true','width':fixWidth(0.15)},"+
    "{'title':'开始时间','field':'startTime','sortable':'true','width':fixWidth(0.2),'formatter':function(value,row,index){return value.substring(0,19);}},"+
    "{'title':'结束时间','field':'endTime','sortable':'true','width':fixWidth(0.2),'formatter':function(value,row,index){return value.substring(0,19);}},"+
    "{'title':'状态','field':'openClose','sortable':'true','width':fixWidth(0.15),'formatter':function(value,row,index){"+
    "    if (row.openClose=='1'){" +
    "        return '待确认';" +
    "    } else if(row.openClose=='2'){" +
    "        return '待生效';" +
    "    } else if(row.openClose=='3'){" +
    "        return '已生效';" +
    "    } else if(row.openClose=='4'){" +
    "        return '终止';" +
    "    } else if(row.openClose=='5'){" +
    "        return '取消';" +
    "    }" +
    "}},"+
    "{'title':'性质','field':'exp1','sortable':'true','width':fixWidth(0.15),'formatter':function(value,row,index){"+
    "    if (row.exp1=='sq'){" +
    "        return '授权';" +
    "    } else if(row.exp1=='qj'){" +
    "        return '外出告知';" +
    "    } else if(row.exp1=='zsq'){" +
    "        return '再授权';" +
    "    }" +
    "}},"+
    "{'title':'操作','field':'opt','sortable':'true','width':fixWidth(0.15),'formatter':function(value,row,index){"+
    "var str='';"+
    "var id="'"+row.id+"'";"+
    "var exp1="'"+row.exp1+"'";"+
    "if(row.exp2=='Y'){"+
    "str += '<a class="ace_button" href="#" onclick="stopOrdeleteOnlick('+id+','+exp1+')">取消</a>&nbsp;';" +
    "}"+
    "return str;"+
    "}}"+
    "]]";
column = eval(column);
$("#tEmDutyAuthorizztionList").datagrid({
    columns:column,
    rownumber:true,
    fitcolumns:true,
    idField:"id",
    sortOrder:"desc",
    sortName:"endTime",
    fit:"true",
    queryMode:"group"
});

});


//设置宽度百分比

function fixWidth(percent) {
    return document.documentElement.clientWidth * percent; //这里你可以自己做调整
}
//设置高度百分比
function fixHeight(percent) {
return document.documentElement.clientHeight * percent - 9; //这里你可以自己做调整
}