settimeout 怎么取消?

Question

全局 var time1;
clearTimeout(time1);
 
time1=window.setTimeout(function(){f2(mm)},2000);

Answer 1

var running = false;
function f2()
  {
        alert('测试');
   running = false;
  }
function f1()
 {
     if(running == true){
         return;
     }
     running = true;
      var time = window.setTimeout("f2()",2000);
}

Answer 2

var time;
function f2()
  {
    alert('测试');
  }
function f1()
 {
      time = window.setTimeout("f2()",2000);
      clearTimeout(time);}
</script>
<input type="text" onclick="f1()"/>