js计算器
快捷键：等于(回车)；清空（ESC）；小键盘
效果图：
代码：
<!DOCTYPE HTML>
<html>
<body>
<p>js计算器</p>
<p>快捷键：等于（回车）；清空（ESC）；小键盘</p>
<style><!--
.tdBtn input
{
width:50px;
font-weight:bold;
margin:1px;
font-size:16px;
}
.tdExtBtn input
{
height:60px;
line-height:60px;
}
--></style>
<script type="text/javascript">// <![CDATA[
function getObj(id)
{
return document.getElementById(id);
}
function pageLoad()
{
var inputs = document.getElementById('trCalc').getElementsByTagName('input');
for(var i=0; i<inputs.length; i++)
{
if(inputs[i].type == 'button')
{
inputs[i].onclick = btn_onclick;
}
}
getObj('txt').focus();
getObj('txt').value = '0';
}
function btn_onclick()
{
var txt = getObj('txt');
showText(this.value);
}
function keyDown(evt)
{
evt = evt || window.event;
switch(evt.keyCode)
{
case 13:
showText('等于');
evt.returnValue = false;
break;
case 27:
showText('清空');
evt.returnValue = false;
break;
case 107:
showText('+');
evt.returnValue = false;
break;
case 109:
showText('-');
evt.returnValue = false;
break;
case 106:
showText('*');
evt.returnValue = false;
break;
case 111:
showText('/');
evt.returnValue = false;
break;
case 110:
showText('.');
evt.returnValue = false;
break;
default:
if(txt.value == '0')
{
txt.value = '';
}
break;
}
}
var value = 0;
var op = '';
function showText(str)
{
var spanOp = getObj('spanOp');
if('0123456789.'.indexOf(str) != -1)
{
if(txt.value == '0')
{
txt.value = '';
}
txt.value += str;
return;
}
if(str == '+/-')
{
if(txt.value.indexOf('-') == 0)
{
txt.value = txt.value.substr(1);
}
else
{
txt.value = '-' + txt.value;
}
return;
}
if('+-*/'.indexOf(str) != -1)
{
if(txt.value == '0' && str == '/')
{
alert('除零错误！');
return;
}
eval('value ' + op + '= ' + txt.value);
txt.value = '0';
op = str;
spanOp.innerHTML = op;
return;
}
if(str == '等于' || str == '=')
{
if(op != '')
{
eval('value ' + op + '= ' + txt.value);
op = '';
spanOp.innerHTML = '';
}
txt.value = value;
}
if(str == '清空')
{
txt.value = '0';
value = 0;
op = '';
spanOp.innerHTML = '';
}
}
// ]]></script>
<div>
<table>
<tbody>
<tr>
<td colspan="2"><input id="txt" style="font-size: 23px; font-weight: bold; color: blue; text-align: right; ime-mode: disabled; width: 255px;" onkeydown="keyDown(event);" type="text" /> <span id="spanOp"> </span></td>
</tr>
<tr id="trCalc">
<td class="tdBtn">
<input type="button" value="7" />
<input type="button" value="8" />
<input type="button" value="9" />
<input type="button" value="+" /><br />
<input type="button" value="4" />
<input type="button" value="5" />
<input type="button" value="6" />
<input type="button" value="-" /><br />
<input type="button" value="1" />
<input type="button" value="2" />
<input type="button" value="3" />
<input type="button" value="*" /><br />
<input type="button" value="0" />
<input type="button" value="+/-" />
<input type="button" value="." />
<input type="button" value="/" />
</td>
<td class="tdExtBtn">
<input type="button" value="清空" /><br />
<input type="button" value="等于" />
</td>
</tr>
</tbody>
</table>
</div>
<script type="text/javascript">
pageLoad();
</script>
</body>
</html>