12.5 HTML_WHITELIST Function

The HTML_WHITELIST function performs HTML escape on all characters in the input text except the specified whitelist tags. This function can be useful if the input text contains simple html markup but a developer wants to ensure that an attacker cannot use malicious tags for cross-site scripting.

Syntax

APEX_ESCAPE.HTML_WHITELIST (
    p_html IN VARCHAR2,
    p_whitelist_tags IN VARCHAR2 DEFAULT c_html_whitelist_tags )
    return VARCHAR2;

Parameters

Table 12-5 HTML_WHITELIST Function Parameters

Parameter	Description
`p_html`	The text string that is filtered.
`p_whitelist_tags`	The comma separated list of tags that stays in `p_html`.

Example

This example shows how to use HTML_WHITELIST to remove unwanted html markup from a string, while preserving whitelisted tags.

begin     sys.htp.p(apex_escape.html_whitelist(         '<h1>Hello<script>alert("XSS");</script></h1>')); end;