What is this user-input regex checking for? /^[^<">]*$/

Question

This regex is used to check some user input:

/^[^<">]*$/

What is it checking for?

Answer 1

It's checking for a line (possibly empty) that doesn't contain <, > or ".

Answer 2

It's checking for double quotes (") and angle brackets (<>).

/^[^<">]*$/

/^ means the start of the string.
[^<">] means not <, ", or >.
* means zero or more of the previous expression.
$/ means the end of the string.

So it's checking whether the input consists of zero or more characters, none of which are <>".

Answer 3

That none of these characters appear on the line: < > "

Answer 4

Any string that doesn't contain <"> characters.

Answer 5

This is probably a simple regex being used to check for an xml element with an attribute.

Answer 6

It ensures that the input contains no < " or > characters.

^ at the beginning matches the literal beginning of the string.

[^<">]* matches 0 or more characters that ARENT one of the three: <">.

$ at the end matches the literal end of the string.

Answer 7

/^[^<">]*$/

To be clear: it does not match any string that contains <, >, or ".

It will match anything else.

Answer 8

Matching a string against this RegEx will return FALSE if any double-quotes or brackets exist in the string. If none exist, or the string is empty, it will return TRUE.