JavaScript 实现简单计算器
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=(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>
HTML代码如下：
<body> <div id="calculator"> <div id="logo"> <span id="name">简单的计算器</span> <span id="verson">@MrJu</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"> <!--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="*" 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> </body>
Css代码：
<style> *{ 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{ height: 20px; } #name{ float:left; line-height:30px; } #verson{ float:right; line-height:30px; } #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 .buttons{ float:left; width: 42px; height: 36px; text-align:center; background-color:lightgray; margin: 0 17px 20px 0; } </style>
下面是转化为JQuery代码有bug: back建不好用，求大神评论：
JQuery代码：
<script>
var num = ""; // 定义第一个输入的数据
$(function () {
$('.buttons').click(function () {
var value =$(this).val();
if (value=="="){
//计算输入结果
var a = eval(num);
$('#screenName').val(a);
num = a;
}else if (value=='C'){
//清零
num = "";
$('#screenName').val(num);
}else if (value == 'Back') {
//后退一步 有毛病
var arr = $("#screenName").val();
arr = arr.substring(0, arr.length - 1);
}else {
//获取输入值
num += value;
$('#screenName').val(num);
}
})
})
</script>
HTML代码：
<body> <div id="calculator"> <div id="logo"> <span id="name">简单的计算器</span> <span id="owner">@MrJu</span> </div> <div id="shuRu"> <!--screen输入栏--> <div class="screen"> <input type="text" id="screenName" class="screen" value=""> </div> </div> <div id="keys"> <!--第一排--> <input type="button" id="7" value="7" class="buttons"> <input type="button" id="8" value="8" class="buttons"> <input type="button" id="9" value="9" class="buttons"> <input type="button" id="Back" value="Back" class="buttons"> <input type="button" id="C" value="C" class="buttons" style="margin-right:0px"> <!--第二排--> <input type="button" id="4" value="4" class="buttons"> <input type="button" id="5" value="5" class="buttons"> <input type="button" id="6" value="6" class="buttons"> <input type="button" id="*" value="*" class="buttons"> <input type="button" id="/" value="/" class="buttons" style="margin-right:0px"> <!--第三排--> <input type="button" id="1" value="1" class="buttons"> <input type="button" id="2" value="2" class="buttons"> <input type="button" id="3" value="3" class="buttons"> <input type="button" id="+" value="+" class="buttons"> <input type="button" id="-" value="-" class="buttons" style="margin-right:0px"> <!--第四排--> <input type="button" id="0" value="0" class="buttons"> <input type="button" id="00" value="00" class="buttons"> <input type="button" id="." value="." class="buttons"> <input type="button" id="%" value="%" class="buttons"> <input type="button" id="eva" value="=" class="buttons" style="margin-right:0px"> </div> </div> </body>