Javascript regular expression for negative Numbers with decimal

Question

I want to test for this input: [an optional negative sign] 2 digits [an optional . and an optional digit] like this:

-34 or -34.5333 or

Answer 1

Perhaps regex is not needed.

function validate(val){
    return isNaN(val)?false:(Math.abs(Math.floor(val)).toString().length==2);
}