Tests if a string can be parsed as a number which may contain a fractional component. May be negative. Plus sign and scientific notation are not supported.
Valid: '1234', '-1234', '-1.234', '1234.1234'
Not valid: '1.1.1', '+1', '.1', '-.1', '10.1234E10', '1.'
Submitted by Gary Ott - 9 years ago