JavaScript regular expression currency decimal only

Question

My knowledge of regex is very weak. So far I have manage to create an expression that verifies if a string is an integer or not. The issues is that I only want decimal numbers NO WHOLE numbers at all.

Regex:

"currency": {
                    "regex": /^\s*(\+|-)?((\d+(\.\d\d)?)|(\.\d\d))\s*$/,
                    "alertText": "* Not a valid decimal number."
                },

Example

valid:
45.00

invalid:
$45.00
45
$45

Answer 1

You could use:

/^\s*[+-]?(\d+\.\d\d)\s*$/

If you want to allow .50 change \\d+ to \\d* .

Answer 2

If the number of decimal points can be larger than 2 then you can use:

^\s*[+-]?\d*\.\d+\s*$

This will handle 10.50, .50, 10.5123456 etc