计算器
<!DOCTYPE html>
<html lang="zn">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<input type="text" id="txt1">
<select name="" id="slt">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type="text" id="txt2">
<button onclick="show()">=</button>
<input type="text" id="jieguo">
<script>
var jg;
var oT=document.getElementById('txt1');
var oS=document.getElementById('txt2');
var slt=document.getElementById('slt');
var jG=document.getElementById('jieguo');
function show(){
switch(slt.value){
case '+':
jg=(parseFloat(oT.value)+parseFloat(oS.value));
break;
case '-':
jg=(parseFloat(oT.value)-parseFloat(oS.value));
break;
case '*':
jg=(parseFloat(oT.value)*parseFloat(oS.value));
break;
case '/':
jg=(parseFloat(oT.value)/parseFloat(oS.value));
break;
}
jG.value = jg;
}
</script>
</body>
</html>