Javascript RegEx partial match

Question

I have a regular expression pattern, which validates for a three digit number

/^\\d{3}$/.test(\"123\")   // true
/^\\d{3}$/.test(\"123.\")  // false
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Answer 1

You can specify a range in the expression so that it matches anything between one and three digits like so:

/^\d{1,3}$/.test("1")  // true
/^\d{1,3}$/.test("12")  // true
/^\d{1,3}$/.test("123a")  // false

Answer 2

According to your last edit, this should work:

/^#[a-fA-F0-9]{0,6}$/

Answer 3

You would be better off by using a library like maskedinput.js. You can then setup your text input like follows:

jQuery(function($){
    $("#your_input").mask("999");
});

UPDATE

you can use a validator for forms and preset specific types of fields to validate

Answer 4

Just provide a regex that allows for partial matches. e.g. /^\d{1,3}$/

Answer 5

You could partially validate the email address by using ()? for more letters and/or characters. Every ()? going deeper in the validation tree.

The following regular expression pattern validates email address letter by letter.

^[a-zA-Z]+(@{1}[a-zA-Z]*(\.{1}[a-zA-Z]*)?)?$

It does not take into account every possibility out there, but for basic ones like aa@bb.dd it works just fine and there's room to improve it further.

Answer 6

You'll want to use explicit "|" partial matches. For your color matching example it's pretty simple, you just need to explicitly match an empty string partial

/^(|#[a-f0-9]{0,6})$/i.test(inputStr)

For an email it's more complicated since there are more partial match combinations

/^(|\w+|\w+@|\w+@\w+|\w+@\w+\.|\w+@\w+\.\w+)$/.test(inputStr)

Note that you can't get away with something like /^(|\w*@|...)$/ since that matches @blah.com which isn't a valid partial input.