– Common Function Library Project

StripTags(stripmode, mytags, mystring [, findonly])

Last updated September 22, 2004

Version: 2 | Requires: ColdFusion 5 | Library: StrLib

Rated 5 time(s). Average Rating: 3.4

Enter a mode, list of tags and a string to either strip all tags in or not in the list from the string, or return the first substring matching or not matching an item in the list.

Return Values:
Returns either a string or the first instance of a match.


view plain print about
<cfset mymodes = ListToArray("allow,disallow")>
<cfset mytags = ListToArray("a,div,span,br,table|cf*|%*","|")>
<cfset far = structnew()>
<cfset far["true"] = "find only">
<cfset far["false"] = "find and replace">
<cfsavecontent variable="variables.teststring">
This is a string containing a <a href="" target="_blank">link</a>
and some <div>other</div> miscellaneous <table>tags</table><span>whether</span>
<br /> you like them or #chr(asc("<"))#cfabort> not. <#chr(asc("%"))#=with some asp stuff %>

<cfloop index="
y" from="1" to="#arraylen(mytags)#">
    <cfloop index="
x" from="1" to="#arraylen(mymodes)#">
        <cfloop index="
z" list="true,false">
            <p><b>#mymodes[x]# #mytags[y]# #far[z]#</b><br />



Name Description Required
stripmode A string, disallow or allow. Specifies if the list of tags in the mytags attribute is a list of tags to allow or disallow. Yes
mytags List of tags to either allow or disallow. Yes
mystring The string to check. Yes
findonly Boolean value. If true, returns the first match. If false, all instances are replaced. No

Full UDF Source:

view plain print about
 * Strip xml-like tags from a string when they are within or not within a list of tags.
 * @param stripmode      A string, disallow or allow. Specifies if the list of tags in the mytags attribute is a list of tags to allow or disallow. (Required)
 * @param mytags      List of tags to either allow or disallow. (Required)
 * @param mystring      The string to check. (Required)
 * @param findonly      Boolean value. If true, returns the first match. If false, all instances are replaced. (Optional)
 * @return Returns either a string or the first instance of a match. 
 * @author Isaac Dealey ( 
 * @version 2, September 22, 2004 

function stripTags(stripmode,mytags,mystring) {
    var spanquotes = "([^"">]*""[^""]*"")*";
    var spanstart = "[[:space:]]*/?[[:space:]]*";
    var endstring = "[^>$]*?(>|$)";
    var x = 1;
    var currenttag = structNew();
    var subex = "";
    var findonly = false;
    var cfversion = iif(structKeyExists(GetFunctionList(),"getPageContext"), 6, 5);
    var backref = "\\1"// this backreference works in cf 5 but not cf mx
    var rexlimit = len(mystring);

    if (arraylen(arguments) gt 3) { findonly = arguments[4]; }
    if (cfversion gt 5) { backref = "\#backref#"} // fix backreference for mx and later cf versions
    else { rexlimit = 19000; } // limit regular expression searches to 19000 characters to support CF 5 regex character limit

    if (len(trim(mystring))) {
        // initialize defaults for examining this string
        currenttag.pos = ListToArray("0");
        currenttag.len = ListToArray("0");

        mytags = ArrayToList(ListToArray(mytags)); // remove any empty items in the list
        if (len(trim(mytags))) {
            // turn the comma delimited list of tags with * as a wildcard into a regular expression
            mytags = REReplace(mytags,"[[:space:]]","","ALL");
            mytags = REReplace(mytags,"([[:punct:]])",backref,"ALL");
            mytags = Replace(mytags,"\*","[^$>[:space:]]*","ALL");
            mytags = Replace(mytags,"\,","[$>[:space:]]|","ALL");
            mytags = "#mytags#[$>[:space:]]";
        } else { mytags = "$"} // set the tag list to end of string to evaluate the "allow nothing" condition

        // loop over the string
        for (x = 1; x gt 0 and x lt len(mystring); x = x + currenttag.pos[1] + currenttag.len[1] -1)
            // find the next tag within rexlimit characters of the starting point
            currenttag = REFind("<#spanquotes##endstring#",mid(mystring,x,rexlimit),1,true); 
            if (currenttag.pos[1])
                // if a tag was found, compare it to the regular expression
                subex = mid(mystring,x + currenttag.pos[1] -1,currenttag.len[1]); 
                if (stripmode is "allow" XOR REFindNoCase("^<#spanstart#(#mytags#)",subex,1,false) eq 1)
                    if (findonly) { return subex; } // return invalid tag as an error message
                    else { // remove the invalid tag from the string
                        myString = RemoveChars(myString,x + currenttag.pos[1] -1,currenttag.len[1]);
                        currenttag.len[1] = 0; // set the length of the tag string found to zero because it was removed
            // no tag was found within rexlimit characters
            // move to the next block of rexlimit characters -- CF 5 regex limitation
            else { currenttag.pos[1] = rexlimit; }
    if (findonly) { return ""} // return an empty string indicating no invalid tags found
    else { return mystring; } // return the new string discluding any invalid tags
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