checking fields

[bunny1]

i am checking that a field only contains numbers using the following code

preg_match('/^[0-9\" "]*$/')

i want to allow a decimal point in this field.
How can i make sure the only non numerical character allowed is a "."

thanks

[bokeh]

Use is_numeric() instead of preg_match would be easiest.

[bunny1]

thank you