I have this very basic calculator:
<html>
<body>
<form name="form">
<input type="text" name="num1" />
<input type="text" name="num2" />
<input type="text" name="res" />
<input type="button" value="+" onclick="form.res.value = form.num1.value + form.num2.value" />
</form>
</body>
</html>
But it treats form.num1.value and form.num2.value as string and because of it the result is the concatenation of these values instead of addition.
How to treat them as numbers?
I have this very basic calculator:
<html>
<body>
<form name="form">
<input type="text" name="num1" />
<input type="text" name="num2" />
<input type="text" name="res" />
<input type="button" value="+" onclick="form.res.value = form.num1.value + form.num2.value" />
</form>
</body>
</html>
But it treats form.num1.value and form.num2.value as string and because of it the result is the concatenation of these values instead of addition.
How to treat them as numbers?
Share Improve this question asked Dec 6, 2013 at 12:59 BillieBillie 9,14612 gold badges42 silver badges71 bronze badges4 Answers
Reset to default 6Wrap each value in a parseInt(value, 10) or parseFloat(value).
Shortest way is the unary plus operator, which converts to Number:
+form.num1.value + +form.num2.value
Note: it will return NaN for mixed inputs like "10 potatoes". To avoid that, you can use parseInt or parseFloat.
Try to convert them to number like this:
onclick="Numberform.res.value = Number(form.num1.value) + Number(form.num2.value)"
Convert them to numbers with the + operator or parseFloat.