Entry to regular expression: submode

Source: Internet
Author: User

In a regular expression, you can use "(" and ")" to enclose the sub-strings in the pattern to form a sub-pattern. When the sub-mode is regarded as a whole, it is equivalent to a single character.

Next we will try to match all the line breaks, including <br>, <br/>, and <br/>.

(<br\s*\/?>)
Effect demonstration
Welcome to bkjia.com.<br> Welcome to bkjia.com. *2<br><br/><br /> Welcome to bkjia.com. *3<br>>>>

This example code
function reg_replace(){var test = document.getElementById("test");var regex = /(<br\s*\/?>)/g;test.innerHTML = test.innerHTML.replace(regex,"<span style='background-color:orange'>$1</span>");}

We can understand the matching process as follows: Sub-mode "(<br \ s * \/?> )" First, match all "<br>", "<br/>", or "<br/>", and then treat each matching result as a whole (equivalent to a single character). Then, match the entire text that appears two or more times in a row.

Additional reading

The topic list of this article is as follows:

  1. What is a regular expression?
  2. Getting started with regular expressions: match a Fixed Single Character
  3. Getting started with regular expressions: matching any single character
  4. Getting started with regular expressions: Use character groups
  5. Getting started with regular expressions: Use character ranges in character groups
  6. Getting started with regular expressions: Use of assense character groups
  7. Getting started with regular expressions: matching null characters
  8. Getting started with regular expressions: Match one or more characters
  9. Regular Expression: matches zero or multiple characters.
  10. Regular Expression entry: matches zero or one string.
  11. Getting started with regular expressions: Match fixed numbers of Characters
  12. Getting started with regular expressions: match the number of characters in a range
  13. Getting started with regular expressions: greedy matching
  14. Getting started with regular expressions: inert matching
  15. Entry to Regular Expressions: two matching Modes
  16. Getting started with regular expressions: match word boundaries
  17. Getting started with regular expressions: boundary definition and relativity
  18. Getting started with regular expressions: Match non-word boundaries
  19. Getting started with regular expressions: match the beginning and end of a text
  20. Entry to regular expression: submode
  21. Regular Expression entry: "or" Match
  22. Getting started with regular expressions: replacing with referenced text
  23. Getting started with regular expressions: unmatched
  24. Regular Expression Summary: Regular Expressions in JavaScript
  25. Regular Expression Summary: advanced application of regular expressions in js

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