Regular expressions for HTML

Regular expressions can be used to find HTML code which can then be used for cleaning or in CMS’s. Here are a couple I’ve been looking for.

To find all tags on a page

</?\w+((\s+\w+(\s*=\s*(?:”.*?”|’.*?’|[^'">\s]+))?)+\s*|\s*)/?>

To find a class or id tag

class=”[^"]*["]|id=”[^"]*["]|style=”[^"]*["]

• \sid=” – the \s represent any type of space (tab,
  space, form/line feed). Checking for a space is important for some tags
  as it ensures that you are not picking up fragments of other
  attributes. For instance, align=” would pick up both align and valign tag attributes.
• [^”]*
  - this matches any character except the double quote (”) character and
  continues to until it finds a double quote. This is because the [^”]
  rule is proceeded by a asterisk (*).
• ” – picks up the closing double quote to complete the regex.
• |\sclass=”[^”]*”|
  \sstyle=”[^”]*”- the vertical line character (|) signifies an either/or
  rule. Therefore, it will find all id, class and style tags that begin
  and end with double quotes

Replacing tags in dreamweaver

In the following example:

<th>Column Header 1</th>

We want to replace the th tag contents with a link. Use parenthesis
<th[^>]*>([^<]*)</th>

<th><a title=”Sort By $1″ href=”#”>$1</a></th>

Find image tags

<img[^>]*[>]

Find links

<a href=”[^>]*[>]

or

<a[\s]+[^>]*?href[\s]?=[\s\"\']+(.*?)[\"\']+.*?>([^<]+|.*?)?<\/a>

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