html5 pattern match float and/or percentage

Question

I'm working with form validation and want to use pattern attribute for validate the input field. The field has the following criteria:

1. It must be a number (Integer or Float)
2. Can allow up to 2 decimal point (e.g.: 100.24)
3. Only one dot is allowed (e.g.: 100.25.35 is not valid)
4. May end with a percent(%) sign (But not always necessary)

So what should be the exact pattern RegEx for that. I'm trying with the following code but how to implement the percent condition?

<input type="text" 
       pattern="[0-9]+([\.][0-9]{0,2})?" 
       title="This must be a number with up to 2 decimal places and/or %">

Solution

You are almost there. Add %? to your pattern:

input:invalid {
  color: red;
}

<input type="text"
       pattern="[0-9]+(\.[0-9]{1,2})?%?"
       title="This must be a number with up to 2 decimal places and/or %">