javascript平时小例子⑥(简易计算器的制作)

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script>
window.onload = function()
{
var oTxt1 = document.getElementById("txt1");
var oTxt2 = document.getElementById("txt2");

var oSel1 = document.getElementById("sel1");

var oBtn1 = document.getElementById("btn1");
var oSpa1 = document.getElementById("spa1");

oBtn1.onclick=function()
{
var a1 = parseFloat(oTxt1.value);
var a2 = parseFloat(oTxt2.value);

var result;

switch(oSel1.value)
{
case "+":result=a1+a2;
break;
case "-":result=a1-a2;
break;
case "*":result=a1*a2;
break;
case "/":result=a1/a2;
break;
case "%":result=a1%a2;
break;

}
oSpa1.innerHTML = result;
}

}
</script>
</head>