+ 4

Is there a keyword for number?

I'm trying to make a calculator, and I want there to be an alert saying that the value has to be a number if what the user typed is not, but I don't know how to say that. Any ideas? https://code.sololearn.com/WS5nmS4omS32/?ref=app

5th Feb 2018, 10:45 PM
jacksonofgames 28
jacksonofgames 28 - avatar
3 odpowiedzi
+ 4
Thank you!
5th Feb 2018, 11:19 PM
jacksonofgames 28
jacksonofgames 28 - avatar
+ 3
There is an event called 'onkeypress' within that evet you can chek if pressed key is numeric <!-- html --> <input type="text" onkeypress="isNumeric(ev)"> // JavaScript function isNumeric(ev){ if (ev.charCode < 48 && ev.charCode > 57){ alert('only number please'); return false; } }
5th Feb 2018, 11:51 PM
Ahmad
Ahmad - avatar
+ 2
The condition isNaN checks to see if the variable is not a number (NaN), and returns true if it is. You can use this in an if statement to check if it is a number by reversing the condition to !isNaN, which runs the statements only if it is a number. Here's an example code: https://code.sololearn.com/WaB1277ApdI0/?ref=app
5th Feb 2018, 11:12 PM
Faisal
Faisal - avatar