How to Create A Simple Calculator in JavaScript
<!DOCTYPE HTML> | |
<html lang="en"> | |
<head> | |
<meta charset="utf-8"> | |
<title>A Simple Calculator</title> | |
<link href="https://fonts.googleapis.com/css?family=Inconsolata" rel="stylesheet"> | |
<style> | |
* { | |
font-family: 'Inconsolata', monospace; | |
color: #555; | |
} | |
body { | |
background-color: #3fb399; | |
} | |
.container { | |
width: 320px; | |
background-color: white; | |
margin: 120px auto; | |
} | |
table { | |
width: 100%; | |
border-color: #f4f4f4; | |
} | |
td { | |
width: 25%; | |
} | |
button { | |
width: 100%; | |
height: 70px; | |
font-size: 24px; | |
background-color: white; | |
border: none; | |
} | |
#inputLabel { | |
height: 120px; | |
font-size: 40px; | |
vertical-align: bottom; | |
text-align: right; | |
padding-right: 16px; | |
background-color: #ececec; | |
} | |
</style> | |
</head> | |
<body> | |
<div class="container"> | |
<table border="1" cellspacing="0"> | |
<tr> | |
<td colspan="4" id="inputLabel">0</td> | |
</tr> | |
<tr> | |
<td colspan="3"><button onclick="pushBtn(this);">AC</button></td> | |
<td><button onclick="pushBtn(this);">/</button></td> | |
</tr> | |
<tr> | |
<td><button onclick="pushBtn(this);">7</button></td> | |
<td><button onclick="pushBtn(this);">8</button></td> | |
<td><button onclick="pushBtn(this);">9</button></td> | |
<td><button onclick="pushBtn(this);">*</button></td> | |
</tr> | |
<tr> | |
<td><button onclick="pushBtn(this);">4</button></td> | |
<td><button onclick="pushBtn(this);">5</button></td> | |
<td><button onclick="pushBtn(this);">6</button></td> | |
<td><button onclick="pushBtn(this);">-</button></td> | |
</tr> | |
<tr> | |
<td><button onclick="pushBtn(this);">1</button></td> | |
<td><button onclick="pushBtn(this);">2</button></td> | |
<td><button onclick="pushBtn(this);">3</button></td> | |
<td><button onclick="pushBtn(this);">+</button></td> | |
</tr> | |
<tr> | |
<td colspan="2"><button onclick="pushBtn(this);">0</button></td> | |
<td><button onclick="pushBtn(this);">.</button></td> | |
<td><button onclick="pushBtn(this);">=</button></td> | |
</tr> | |
</table> | |
</div> | |
<script> | |
var inputLabel = document.getElementById('inputLabel'); | |
function pushBtn(obj) { | |
var pushed = obj.innerHTML; | |
if (pushed == '=') { | |
// Calculate | |
inputLabel.innerHTML = eval(inputLabel.innerHTML); | |
} else if (pushed == 'AC') { | |
// All Clear | |
inputLabel.innerHTML = '0'; | |
} else { | |
if (inputLabel.innerHTML == '0') { | |
inputLabel.innerHTML = pushed; | |
} else { | |
inputLabel.innerHTML += pushed; | |
} | |
} | |
} | |
</script> | |
</body> | |
</html> |
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