菜鸟求教怎么用setInterval

[xcyshys]

<div id="content" style="display:none;">0</div>
<div id="content1" contenteditable = "true"></div>
<div id="content2"></div>
<button id="button1">开始</button>
<button id="button2">结束</button>
<script>
var oDiv = document.getElementById("content");
var oDiv1 = document.getElementById("content1");
var oDiv2 = document.getElementById("content2");
var b1 = document.getElementById("button1");
var b2 = document.getElementById("button2");


function R(a,b){
var i = Math.random()*(b-a)+a;
return Math.ceil(i);
}

b1.onclick = function b1(){
var a = self.setInterval("R()",50);
oDiv2.innerHTML = R(+oDiv.innerHTML,+oDiv1.innerHTML);
}

</script>
这个下划线的不会用,是希望能点一下开始一直重复运行找随机数的函数,点一下结束就暂停并输出

[slwsss]

function R(a,b){ var i = Math.random()*(b-a)+a; return Math.ceil(i); } var t; b1.onclick = function(){ t = setInterval(function(){ oDiv2.innerHTML = R(+oDiv.innerHTML,+oDiv1.innerHTML); },50); } b2.onclick=function(){clearInterval(t)}

[xcyshys]

谢谢大神