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[Java教程]JAVASCRIPT实现简单计算器


最终效果如下图-2,有bug:就是整数后点击%号结果正确,如果小数后面点击%的话结果就错误!其他都正常,求指点:input的value是string类型的,在JS中改如何正确处理下图-1中的if部分??

图-1

图-2

HTML代码如下

<body><div id="calculator">  <div class="LOGO">    <span class="name">简单的计算器</span>    <span class="verson">@walker</span>  </div>  <div id="shuRu">    <!--screen输入栏-->    <div class="screen">      <input type="text" id="screenName" name="screenName" class="screen">    </div>  </div>  <div id="keys">    <!-- j -->    <!--第一排-->    <input type="button" id="7" onclick="jsq(this.id)" value="7" class="buttons">    <input type="button" id="8" onclick="jsq(this.id)" value="8" class="buttons">    <input type="button" id="9" onclick="jsq(this.id)" value="9" class="buttons">    <input type="button" id="Back" onclick="tuiGe()" value="Back" class="buttons">    <input type="button" id="C" onclick="clearNum()" value="C" class="buttons" style="margin-right:0px">    <!--第二排-->    <input type="button" id="4" onclick="jsq(this.id)" value="4" class="buttons">    <input type="button" id="5" onclick="jsq(this.id)" value="5" class="buttons">    <input type="button" id="6" onclick="jsq(this.id)" value="6" class="buttons">    <input type="button" id="*" onclick="jsq(this.id)" value="X" class="buttons">    <input type="button" id="/" onclick="jsq(this.id)" value="/" class="buttons" style="margin-right:0px">    <!--第三排-->    <input type="button" id="1" onclick="jsq(this.id)" value="1" class="buttons">    <input type="button" id="2" onclick="jsq(this.id)" value="2" class="buttons">    <input type="button" id="3" onclick="jsq(this.id)" value="3" class="buttons">    <input type="button" id="+" onclick="jsq(this.id)" value="+" class="buttons">    <input type="button" id="-" onclick="jsq(this.id)" value="-" class="buttons" style="margin-right:0px">    <!--第四排-->    <input type="button" id="0" onclick="jsq(this.id)" value="0" class="buttons">    <input type="button" id="00" onclick="jsq(this.id)" value="00" class="buttons">    <input type="button" id="." onclick="jsq(this.id)" value="." class="buttons">    <input type="button" id="%" onclick="jsq(this.id)" value="%" class="buttons">    <input type="button" id="eva" onclick="eva()" value="=" class="buttons" style="margin-right:0px">  </div>  <div class="footer">    <span class="aside">欢迎使用JavaScript计算器</span>      <span class="link">        <a href="#" title="声明" target="_blank">反馈</a>      </span>  </div></div></body>

CSS代码如下:

<style>    /*Basic reset*/*{  margin:0;  padding:0;  box-sizing: border-box;  font: 14px Arial,sans-serif;}html{  height:100%;  background-color:lightslategrey;}#calculator{  margin: 15px auto;  width:330px;  height:400px;  border: 1px solid lightgray;  background-color:darkgrey;  padding:15px;}/*LOGO*/.LOGO{  height:20px;}.LOGO .name{  float:left;  line-height:30px;}.LOGO .verson{  float:right;  line-height:30px;}/*screen*/#shuRu{  margin-top:15px;}.screen{  margin-top:5px;  width:300px;  height:40px;  text-align: right;  padding-right:10px;  font-size:20px;}#keys{  border:1px solid lightgray;  height:223px;  margin-top:25px;  padding:8px;}#keys .last{  margin-right:0px;}.footer{  margin-top:20px;  height:20px;}.footer .link{  float:right;}#keys .buttons{  float:left;  width: 42px;  height: 36px;  text-align:center;  background-color:lightgray;  margin: 0 17px 20px 0;}  </style>

javascript代码如下:

<script>    var num = 0; // 定义第一个输入的数据    function jsq(num) {      //获取当前输入			if(num=="%"){				document.getElementById('screenName').value=Math.round(document.getElementById('screenName').value)/100;			}else{				document.getElementById('screenName').value += document.getElementById(num).value;			}    }    function eva() {      //计算输入结果      document.getElementById("screenName").value = eval(document.getElementById("screenName").value);    }    function clearNum() {      //清0      document.getElementById("screenName").value = null;      document.getElementById("screenName").focus();    }    function tuiGe() {      //退格      var arr = document.getElementById("screenName");      arr.value = arr.value.substring(0, arr.value.length - 1);    }  </script>