HTML simple calculator with detailed ideas

Time:2019-11-17

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The code is as follows:

<!DOCTYPE html>
<html>
<meta name=”content-type” content=”text/html; charset=UTF-8″>
<head>
<title>Calculator</title>
<! — store the key content as a string in the text box. When the button is “=”, call the eval method to calculate the result and then output the result to the text box — >
<script type=”text/javascript”>
var numresult;
var str;
function onclicknum(nums) {
str = document.getElementById(“nummessege”);
str.value = str.value + nums;
}
function onclickclear() {
str = document.getElementById(“nummessege”);
str.value = “”;
}
function onclickresult() {
str = document.getElementById(“nummessege”);
numresult = eval(str.value);
str.value = numresult;
}
</script>
</head>
<body bgcolor=”affff” >
<! — define key table, each key corresponds to an event trigger — >
<table border=”1″ align=”center” bgColor=”#bbff77″
style=”height: 350px; width: 270px”>
<tr>
<td colspan=”4″>
<input type=”text”
style=”height: 90px; width: 350px; font-size: 50px” />
</td>
</tr>
<tr>
<td>
<input type=”button” value=”1″ onclick=”onclicknum(1)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”2″ onclick=”onclicknum(2)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”3″ onclick=”onclicknum(3)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”+” onclick=”onclicknum(‘+’)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
</tr>
<tr>
<td>
<input type=”button” value=”4″ onclick=”onclicknum(4)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”5″ onclick=”onclicknum(5)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”6″ onclick=”onclicknum(6)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”-” onclick=”onclicknum(‘-‘)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
</tr>
<tr>
<td>
<input type=”button” value=”7″ onclick=”onclicknum(7)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”8″ onclick=”onclicknum(8)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”9″ onclick=”onclicknum(9)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”*” onclick=”onclicknum(‘*’)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
</tr>
<tr>
<td colspan=”2″>
<input type=”button” value=”0″ onclick=”onclicknum(0)”
style=”height: 70px; width: 190px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”.” onclick=”onclicknum(‘.’)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
<td>
<input type=”button” value=”/”
onclick=”onclicknum(‘/’)”
style=”height: 70px; width: 90px; font-size: 35px”>
</td>
</tr>
<tr>
<td colspan=”2″>
<input type=”button” value=”Del”
onclick=”onclickclear()”
style=”height: 70px; width: 190px; font-size: 35px” />
</td>
<td colspan=”2″>
<input type=”button” value=”=”
onclick=”onclickresult()”
style=”height: 70px; width: 190px; font-size: 35px” />
</td>

</tr>

</table>
</body>
</html>