JavaScript计时器用法分析【setTimeout和clearTimeout】

setTimeout('alert("3s")',5000);

function delay_times(){
   setTimeout('document.getElementById("time_text").innerHTML = "2s"',2000);
   setTimeout('document.getElementById("time_text").innerHTML = "4s"',4000);
   setTimeout('document.getElementById("time_text").innerHTML = "6s"',6000);
}

var count = 0;
var myTimer;
//开始计数
function start_counter(){
   document.getElementById("time_count").innerHTML = count;
   count++;
   myTimer = setTimeout("start_counter()",1000);
}
//停止计数
function s_counter(){
   clearTimeout(myTimer);
}