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

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

I want to use this regex as an input restriction on a textbox.

Basically, if the new value matches, i allow the character to by typed, otherwise i prevent it.

The problem is that no value will ever match, becase "1" is not a full match, and will not allow me to type it.

Is it any way of testing a partial match for a regEx in javascript?

/^\d{3}$/.test("123") // true /^\d{3}$/.test("12") // "partial match" /^\d{3}$/.test("a12") // false

EDIT

\d{3} was just an example. I need to use an email regex or a phone regex as input restriction.

"email" // true "email@" // true "email@@" // false "@yahoo.com" // false

EDIT 2

I have a textBox plugin with input restriction based on a regular expression.

The regular expression can be anything, a hex color Regex, for example: (#){1}([a-fA-F0-9]){6}

I need to prevent user to insert characters which doesn't match the regex.

For example, if the textbox is empty, the first allowed character would be "#".

But if i test "#" character against the regex, it will return "false", because "#" by itself is not valid.

/^(#){1}([a-fA-F0-9]){6}$/.test("#") // false

But at the same time, "#" is partial valid because it respects the regex format (and i should allow user to type it)

What i need to know is if i can verify if a string is a partial match of a regex, so i can allow the user to type the character.

/^(#){1}([a-fA-F0-9]){6}$/.test("#") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#0") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#00") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#000") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#0000") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#00000") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#000000") // is a partial match, allow type /^(#){1}([a-fA-F0-9]){6}$/.test("#000000D") // is not a match, prevent typing
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  • You got answer to your questions? Commented Feb 25, 2015 at 8:24
  • I am facing similar problem :) Commented Feb 25, 2015 at 8:38

6 Answers 6

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2

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 [email protected] it works just fine and there's room to improve it further.

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1

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

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4 Comments

jquery masked input plugin is used for fixed sized strings. I need something generic.
Yes, but that is something different. I need to "validate" on keypress not on blur.
@RaraituL, it shouldn't be hard to modify the script to cater for that need, or even search for something similiar, there are loads of form/input validators on the net :)
i've been doing the research, and is nothing like this :( I don't need a plugin, i need a solution, if exists.
0

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
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The regex which i used just as an example. I will normally use a email regex or a phone regex, and i should allow user to type "email@" but not allow him to type "email@@" for example.
0

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

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0

According to your last edit, this should work:

/^#[a-fA-F0-9]{0,6}$/
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Yes, but this is still hard coded. I need a "is partial match" response from a regex test. Doesn't matter what regex is used. Something like this RegExPlus which is for Java.
It validates, but is still hard coded. I should be able to have any regular expression not just the email case. For example, i might want to have /^[a-Z]{5}@?$/.test("email") // true, and /^[a-Z]{5}@?$/.test("email2") // false
@RaraituL: Sorry, I don't understand what you mean exactly. Could you edit your question and provide some real test cases?
0

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.

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I have a similar scenario, do you know what I need to partial match a string like "ABC12345" where the first part is a series of letters and the second part is numeric?

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