eval方法给力!简易JavaScript计算器

今天看书无意间发现有这么好用的方法，只要传一个算术表达式进去就能得到最终值。这样开发一个计算器变得非常容易了，而且小数点都支持…

下面是我写的代码。高手就别喷啦，我才开始学JavaScript

  

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>JavaScript计算器</title>
<script>

</script>
</head>
<body>
<center><h2>JavaScript计算器</h2>
  <table width="293" border="0">
    <tr style="text-align:center;">
      <td width="241"><input type="text" width="200px" id="textbox"/><input type="button" value="求值" onclick="document.getElementById('textbox').value =eval(document.getElementById('textbox').value)"></td>
    </tr>
  </table>
  <br />
  <table width="200" border="0">
    <tr>
      <td><input type="button" value="7"  onclick="document.getElementById('textbox').value+='7'"/></td>
      <td><input type="button" value="8"  onclick="document.getElementById('textbox').value+='8'"/></td>
      <td><input type="button" value="9"  onclick="document.getElementById('textbox').value+='9'"/></td>
      <td><input type="button" value="加"  onclick="document.getElementById('textbox').value+='+'"/></td>
    </tr>
    <tr>
      <td><input type="button" value="4"  onclick="document.getElementById('textbox').value+='4'"/></td>
      <td><input type="button" value="5"  onclick="document.getElementById('textbox').value+='5'"/></td>
      <td><input type="button" value="6"  onclick="document.getElementById('textbox').value+='6'"/></td>
      <td><input type="button" value="减"  onclick="document.getElementById('textbox').value+='-'"/></td>
    </tr>
    <tr>
      <td><input type="button" value="1" onclick="document.getElementById('textbox').value+='1'"/></td>
      <td><input type="button" value="2"  onclick="document.getElementById('textbox').value+='2'"/></td>
      <td><input type="button" value="3"  onclick="document.getElementById('textbox').value+='3'"/></td>
      <td><input type="button" value="乘"  onclick="document.getElementById('textbox').value+='*'"/></td>
    </tr>
    <tr>
      <td><input type="button" value="."  onclick="document.getElementById('textbox').value+='.'"/></td>
      <td><input type="button" value="0" onclick="document.getElementById('textbox').value+='0'" /></td>
      <td><input type="button" value="R"  onclick="document.getElementById('textbox').value=''"/></td>
      <td><input type="button" value="除"  onclick="document.getElementById('textbox').value+='/'"/></td>
    </tr>
  </table>
<p>&nbsp;</p>
  <p>Powerd By Zmsky</p>
</center>
</body>
</html>

JavaScript计算器

 

Powerd By Zmsky

发布者

Zmsky

http://xloli.net/?page_id=11

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