I have an input field that I will only accept numbers, commas and periods. How can I test if the string is valid according to these rules?
I have tried the following:
var isValid = /([0-9][,][.])$/.test(str);
Your regexp expects one character from the first class (0-9), then one from the second class (comma) then one from the last class (dot). Instead you want any number of characters (*) from the class containing digits, commas and dots (
[0-9,.]). Also, you don't need the parenthesis:
var isValid = /^[0-9,.]*$/.test(str);
DEMO (and explanation): http://regex101.com/r/yK6oF4