先放一个样式图:
源代码如下:
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> *{ padding: 0; margin: 0; } span{ display: inline-block; 100px; height: 100px; background-color: wheat; border-radius: 100px; text-align: center; line-height: 100px; margin: 5px 10px; } div{ 500px; height: 700px; background-color: black; } #ling{ display: inline-block; 225px; height: 100px; background-color: wheat; border-radius: 100px; text-align: center; line-height: 100px; } #result{ display: inline-block; 480px; height: 100px; background-color: white; text-align: right; border-radius: 0; line-height: 100px; color: red; font: 25px/100px "微软雅黑"; } </style> </head> <body> <div id=""> <span id="result"></span><br /> <span onclick="delAll()">del</span> <span onclick="del()">C</span> <span onclick="display('%')">%</span> <span onclick="display('/')">/</span> <span onclick="display(7)">7</span> <span onclick="display(8)">8</span> <span onclick="display(9)">9</span> <span onclick="display('*')">*</span> <span onclick="display(4)">4</span> <span onclick="display(5)">5</span> <span onclick="display(6)">6</span> <span onclick="display('-')">-</span> <span onclick="display(1)">1</span> <span onclick="display(2)">2</span> <span onclick="display(3)">3</span> <span onclick="display('+')">+</span> <span id="ling" onclick="display(0)">0</span> <span onclick="display('.')">.</span> <span onclick="cal()">=</span> </div> <script type="text/javascript"> var osp = document.getElementById("result"); function display(num){ osp.innerHTML=osp.innerHTML+num; } function cal(){ osp.innerHTML=eval(osp.innerHTML); } function delAll(){ osp.innerHTML=""; } function del(){ osp.innerHTML = osp.innerHTML.slice(0,osp.innerHTML.length-1); } </script> </body> </html>
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简单来说,我的做法就是根据需求给每一个按键添加一个点击事件。
先获取到显示器部分:
<span id="result"></span>
var osp = document.getElementById("result");
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利用点击事件将按键的值传给显示部分,用到这个方法的的按键有0~9的数字,小数点,加减乘除和取余(%)的运算符号
<span onclick="display('%')">%</span> <span onclick="display('/')">/</span> <span onclick="display(7)">7</span> <span onclick="display(8)">8</span> <span onclick="display(9)">9</span> <span onclick="display('*')">*</span> <span onclick="display(4)">4</span> <span onclick="display(5)">5</span> <span onclick="display(6)">6</span> <span onclick="display('-')">-</span> <span onclick="display(1)">1</span> <span onclick="display(2)">2</span> <span onclick="display(3)">3</span> <span onclick="display('+')">+</span> <span id="ling" onclick="display(0)">0</span> <span onclick="display('.')">.</span>
function display(num){ osp.innerHTML=osp.innerHTML+num; }
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给等号按键添加的方法如下,eval方法会自动进行运算。
<span onclick="cal()">=</span>
function cal(){ osp.innerHTML=eval(osp.innerHTML); }
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del按键用来清空显示器中的内容。这里直接给显示器赋空值就好了
<span onclick="delAll()">del</span>
function delAll(){ osp.innerHTML=""; }
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c键用来删除输入内容的最后一位,此处用到的方法是slice(),拿这里的例子来说:osp.innerHTML.slice(0,osp.innerHTML.length-1);就是截取字符串中索引值0到length-1的部分,包含0不包含length-1,所以刚好能达到我们所要的效果,即删除字符串的最后一位
function del(){ osp.innerHTML = osp.innerHTML.slice(0,osp.innerHTML.length-1); }