input number validation code example
Example 1: html restrict input to numbers
<input type="text" oninput="this.value = this.value.replace(/[^0-9.]/g, '').replace(/(\..*)\./g, '$1');" />
Example 2: number input html
<input id="number" type="number" value="42">
Example 3: input number has empty value
The hack is to use type="tel" instead of type="number".
This solves the 2 main issues:
It pulls up a number keypad on mobile devices
It validates (and is not empty) with numbers or non-numbers as input.