先放一个样式图:

\"\"

 

源代码如下:

<!DOCTYPE html>
<html>
    <head>
        <  charset=\"UTF-8\">
        < ></ >
        <style type=\"text/css\">
            *{
                padding: 0;
                margin: 0;
            }
            span{
                display: inline-block;
                width: 100px;
                height: 100px;
                background-color: wheat;
                border-radius: 100px;
                text-align: center;
                line-height: 100px;
                margin: 5px 10px;
            }
            div{
                width: 500px;
                height: 700px;
                background-color: black;
            }
            #ling{
                display: inline-block;
                width: 225px;
                height: 100px;
                background-color: wheat;
                border-radius: 100px;
                text-align: center;
                line-height: 100px;
            }
            #result{
                display: inline-block;
                width: 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  =\"delAll()\">del</span>
            <span  =\"del()\">C</span>
            <span  =\"display(\'%\')\">%</span>
            <span  =\"display(\'/\')\">/</span>
            <span  =\"display(7)\">7</span>
            <span  =\"display(8)\">8</span>
            <span  =\"display(9)\">9</span>
            <span  =\"display(\'*\')\">*</span>
            <span  =\"display(4)\">4</span>
            <span  =\"display(5)\">5</span>
            <span  =\"display(6)\">6</span>
            <span  =\"display(\'-\')\">-</span>
            <span  =\"display(1)\">1</span>
            <span  =\"display(2)\">2</span>
            <span  =\"display(3)\">3</span>
            <span  =\"display(\'+\')\">+</span>
            <span id=\"ling\"  =\"display(0)\">0</span>
            <span  =\"display(\'.\')\">.</span>
            <span  =\"cal()\">=</span>
        </div>
        <  type=\"text/ \">
            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);
            }
        </ >
    </body>
</html>

 

————
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\");

————
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  =\"display(\'%\')\">%</span>
            <span  =\"display(\'/\')\">/</span>
            <span  =\"display(7)\">7</span>
            <span  =\"display(8)\">8</span>
            <span  =\"display(9)\">9</span>
            <span  =\"display(\'*\')\">*</span>
            <span  =\"display(4)\">4</span>
            <span  =\"display(5)\">5</span>
            <span  =\"display(6)\">6</span>
            <span  =\"display(\'-\')\">-</span>
            <span  =\"display(1)\">1</span>
            <span  =\"display(2)\">2</span>
            <span  =\"display(3)\">3</span>
            <span  =\"display(\'+\')\">+</span>
            <span id=\"ling\"  =\"display(0)\">0</span>
            <span  =\"display(\'.\')\">.</span>
function display(num){
                osp.innerHTML=osp.innerHTML+num;
            }

————
给等号按键添加的方法如下,eval方法会自动进行运算。

<span  =\"cal()\">=</span>
function cal(){
                osp.innerHTML=eval(osp.innerHTML);
            }

————
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  =\"delAll()\">del</span>
function delAll(){
                osp.innerHTML=\"\";
            }

————
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);
            }

 

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