In the below demo the regular expression looks for one or more uppercase or lowercase letters within the character class [A-Za-z], followed with an end of a line anchor $ Some undesired spaces and dashes from the user input can be removed by using the string object replace() method.
The regular expression is used to find the characters and then replace them with empty spaces.
We have used "/" and "-" character as a separator within the date format but you are free to change that separator the way you want.
When you search for data in a text, you can use this search pattern to describe what you are searching for.
A regular expression can be a single character, or a more complicated pattern.
You want to use a simple regex that simply checks whether the input looks like a date, without trying to weed out things such as February 31You might think that something as conceptually trivial as a date should be an easy job for a regular expression. Because dates are such an everyday thing, humans are very sloppy with them. To somebody else, it may be the first working day of the year, if New Year’s Day is on a Friday.
The other issue is that regular expressions don’t deal directly with numbers. That’s because the characters for the digits 0 through 9 occupy consecutive positions in the ASCII and Unicode character tables.
In Java Script, regular expressions are often used with the two string methods: search() and replace().
The demo below , uses a function to check if value in the form field is empty or null.
A simple six digit zipcode can be checked using regular expression which matches exactly six digits : /^d$/ Another way can be /^[0-9][0-9][0-9][0-9][0-9][0-9]$/ , for zipcode with dash in between it can be /^\d-? There may be some form fields whose values must be strictly alphabetic characters, eg: Name, Country, State.
If you want to use async validation you need to use a runtime that supports Promises.
You can tell to use any A compatible promise implemention like this: There are already many validation libraries out there today but most of them are very tightly coupled to a language or framework.