今天的任务
var tbody = document.querySelector('#tab').tBodies[0];
var th = document.querySelector('#tab').tHead.rows[0].cells;
var td = tbody.rows;
for(var i = 0;i < th.length;i++){
th[i].flag = 1;
th[i].onclick = function(){
if(mark == <?php echo (count($hello)-2);?>){
sort(this.getAttribute('data-type'),this.flag,this.cellIndex);
this.flag = -this.flag;
}
};
};