<input type="button" value="开始">

<input type="text">

<input type="button" value="停止">

<script>

var getInput0=document.getElementsByTagName("input")[0];

var getInput1=0;var set;

var getInput2=document.getElementsByTagName("input")[2];

getInput0.onclick=function(){

document.getElementsByTagName("input")[1].value=getInput1

getInput1=getInput1+1;

set=setTimeout("",1000)

}

getInput2.onclick=input2Fn;

function input2Fn(){

clearTimeout(set);

}

</script>