CODEWITHSUNDEEP
javascripthtmlregex
Green Wizard
Green Wizard

Reputation: 3657

regular expression to avoid only special chars

I'm validating a input text box. I'm new to regexp. I want an expression which throws a validation error if all the characters of input are special characters. but it should allow special characters in the string.

-(**&^&)_) ----> invalid.

abcd-as jasd12 ----> valid.

currently validating for numbers and alphabets with /^[a-zA-Z0-9-]+[a-z A-Z 0-9 -]*$/

Upvotes: 2

Views: 8064

Answers (4)

Pedro Lobito
Pedro Lobito

Reputation: 98881

Use negative Lookahead:

if (/^(?![\s\S]*[^\w -]+)[\s\S]*?$/im.test(subject)) {
    // Successful match
} else {
    // Match attempt failed
}

DEMO

EXPLANATION:

^(?!.[^\w -]+).?$

Assert position at the beginning of a line (at beginning of the string or after a line break character) «^»
Assert that it is impossible to match the regex below starting at this position (negative lookahead) «(?!.*[^\w -]+)»
   Match any single character «.*»
      Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
   Match a single character NOT present in the list below «[^\w -]+»
      Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
      A word character (letters, digits, and underscores) «\w»
      The character “ ” « »
      The character “-” «-»
Match any single character «.*?»
   Between zero and unlimited times, as few times as possible, expanding as needed (lazy) «*?»
Assert position at the end of a line (at the end of the string or before a line break character) «$»

Upvotes: 1

Toto
Toto

Reputation: 91375

According to your comment, special characters are !@#$%^&*()_-, so you could use:

var regex = /^[!@#$%^&*()_-]+$/;
if (regex.test(string)) 
    // all char are special

If you have more special char, add them in the character class.

Upvotes: 2

Nambi
Nambi

Reputation: 12042

~[^a-zA-z0-9 ]+~ it will matches if the String doesnot contains atleast one alphabets and numbers and spaces in it.

Demo

Upvotes: 1

Helpful
Helpful

Reputation: 706

/[A-Za-z0-9]/ will match positive if the string contains at least 1 letter or number, which should be the same as what you're asking. If there are NO letters or numbers, that regex will evaluate as false.

Upvotes: 2

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