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@tianmingzuo
Created November 9, 2018 21:56
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<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta charset="utf-8">
<title>JS Calculator</title>
<!--<link rel="stylesheet" type="text/css" href="calculator.css"> -->
<style>
div table{
width: 360px;
height: 460px;
border 5px ridge pink;
margin: 20px auto;
background-color: #81d4fa;
}
.button{
width: 80px;
height: 60px;
text-align: center;
font-size: 26px;
font-weight: bold;
border-radius: 10px;
}
.text{
color: black;
width: 300px;
height: 60px;
margin: 2px 15px 2px 25px;
border-radius: 10px;
text-align: right;
background-color: white;
}
#Exp, #BS, #CE, #Sign{
font-size: 18px;
color: red;
}
</style>
</head>
<body>
<div>
<table>
<tr><td colspan=4 id="calArea" class="text" type="text"></td></tr>
<tr>
<td><input class="button" type="button" value="Exp" id="Exp" onclick="computing(this)"></td>
<td><input class="button" type="button" value="CE" id="CE" onclick="clearAll()"></td>
<td><input class="button" type="button" value="Back" id="BS" onclick="backSpace()"></td>
<td><input class="button" type="button" value="+/-" id="Sign" onclick="exSign()"></td>
</tr>
<tr>
<td><input class="button" type="button" value="1" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="2" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="3" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="4" onclick="getDigits(this)"></td>
</tr>
<tr>
<td><input class="button" type="button" value="5" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="6" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="7" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="8" onclick="getDigits(this)"></td>
</tr>
<tr>
<td><input class="button" type="button" value="9" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="0" onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="." onclick="getDigits(this)"></td>
<td><input class="button" type="button" value="=" onclick="getResult(this)"></td>
</tr>
<tr>
<td><input class="button" type="button" value="+" onclick="computing(this)"></td>
<td><input class="button" type="button" value="-" onclick="computing(this)"></td>
<td><input class="button" type="button" value="*" onclick="computing(this)"></td>
<td><input class="button" type="button" value="/" onclick="computing(this)"></td>
</tr>
</table>
</div>
<script>
var result; //for saving the number before hitting operator signs
var operator; //for saving operator
var isEqualSign = false;
var txt = document.getElementById("calArea");
txt.value = "";
function getDigits(dgt) {
if(isEqualSign) {
isEqualSign = false;
}
if(txt.value.indexOf(".")>-1 && dgt.value===".") {
return false;
}
txt.value += dgt.value;
txt.innerHTML = txt.value;
}
function backSpace() {
txt = document.getElementById("calArea");
txt.value = txt.value.substr(0, txt.value.length-1);
txt.innerHTML = txt.value;
}
function clearAll() {
txt.value = "";
txt.innerHTML = "";
result = "";
operator = "";
isEqualSign = false;
}
function exSign() {
txt.value = parseFloat(txt.value);
if(txt.value === 0) {
txt.value = txt.value;
}else{
txt.value = -txt.value;
}
txt.innerHTML = txt.value;
}
function computing(opSign) {
operator = opSign.value;
if(txt.value==="") {
return false;
}
result = txt.value;
txt.value = "";
}
function getResult() {
var temp = "";
var firstValue = parseFloat(result);
if(operator === "+") {
temp = firstValue + parseFloat(txt.value);
}else if(operator === "-") {
temp = firstValue - parseFloat(txt.value);
}else if(operator === "*") {
temp = firstValue * parseFloat(txt.value);
}else if(operator === "/") {
temp = firstValue / parseFloat(txt.value);
}else if(operator === "Exp") {
temp = firstValue * firstValue;
}
txt.value = temp;
txt.innerHTML = txt.value;
isEqualSign = true;
result = "";
}
</script>
</body>
</html>
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