$.each(jsonarray, function(i, obj) {
 troptions += "<tr data-sort-field-ftime=\""+obj.paiming+"\">"; 
 troptions += "<td>"+(Number(obj.cdsPrem)/unitnow).toFixed(dotnow)+"</td>";
 troptions += "<td>"+(Number(obj.cdjPrem)/unitnow).toFixed(dotnow)+"</td>";
 troptions += "<td>"+(Number(obj.sumPrem)/unitnow).toFixed(dotnow)+"</td>";
 troptions += "<td>"+obj.paiming+"</td>";
 troptions += "</tr>";
 });

//排序處理
 function changepm(){
 var sortType=$("#pm").val();
 var $trList = $("#ta tbody > tr");//獲取現有tr對象
 //冒泡排序 
 for (var i = 0; i < $trList.length - 1; i++) {
 for (var j = 0; j < $trList.length - 1 - i; j++) {
 var value1 = parseInt($trList[j].attributes["data-sort-field-ftime"].nodeValue); 
 var value2 = parseInt($trList[j + 1].attributes["data-sort-field-ftime"].nodeValue);
 if (sortType === "asc" ? value1 > value2 : value1 < value2) {
 var $temp = $trList[j];
 $trList[j] = null;
 $trList[j] = $trList[j + 1];
 $trList[j + 1] = null;
 $trList[j + 1] = $temp;
 }
 }
 } 
 //返回排序后的tr集合
 //將原來的tr清空，再將排序后的tr插入到table的dom中
 console.log($trList);
 $trList.appendTo($("#ta > tbody").empty());
 }