how to give conditions on number in input type=number 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: 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.