The caret character ^ in a regular expression only matches at the beginning of the input, or (for multi-line regular expressions) at the beginning of a line. If it is preceded by a pattern that must match a non-empty sequence of (non-newline) input characters, it cannot possibly match, rendering the entire regular expression unmatchable.

Examine the regular expression to find and correct any typos.

In the following example, the regular expression /\[^.]*\.css/ cannot match any string, since it contains a caret assertion preceded by an escape sequence that matches an opening bracket.

  • Mozilla Developer Network: JavaScript Regular Expressions.
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