ColdFusion 9 ReReplace nth occurence of HTML tag

Question

I have the following HTML stored in a variable in ColdFusion 9. I need to insert a new table row after the 4th </tr>. i.e. before the Submit button.

<form name="form1" id="form1" action="" method="post">
    <table>
    <tr style="visibility:hidden;display:none;"><td> <input type="hidden" id="ref1" name="ref1" value="1" > </td></tr> 
    <tr style="visibility:hidden;display:none;"><td> <input type="hidden" id="ref2" name="ref2" value="2" > </td></tr> 
    <tr>
        <th style="text-align:left;">Name&nbsp;*&nbsp;</th>
        <td><input type="text" name="foo" id="foo" size="30" maxlength="50" value=""></td>
    </tr>
    <tr>
        <th title="Please enter plain text or HTML." style="cursor:help;text-align:left;">Comment&nbsp;*&nbsp;</th>
        <td><textarea name="bar" id="bar" cols="40" rows="10" ></textarea></td>
    </tr>
    <tr>
        <th colspan="1"></th>
        <td>
            <input style="width:80px" type="submit" value="Submit">
            <input style="width:80px" type="button" value="Cancel">
        </td>
    </tr>
</table>

ReReplace seems like the way to go, but I'm having trouble getting the regexp right. Another option would be to split the string and rebuild it with my new HTML in the middle. Any suggestions would be appreciated.

Answer 1

Regex is the wrong tool for this - you want a HTML parser.

Here's how you can do it with JSoup:

<cfsavecontent variable="InputHtml">
    [insert code from question]
</cfsavecontent>

<cfsavecontent variable="NewRow">
    <tr><th>whatever</th><td>stuff</td></tr>
</cfsavecontent>

<!--- Read "Creating Objects From Jar Files" --->
<cfset jsoup = createObject('java','org.jsoup.Jsoup') />

<cfset HtmlDom = jsoup.parse(InputHtml) />

<cfset HtmlDom.select('tr:eq(4)').after( NewRow ) />

<cfoutput>
    <pre>#XmlFormat(HtmlDom.body().html())#</pre>
</cfoutput>

You can see details of what selectors are supported in the JSoup Selector API

If you don't know/care how many lines are in the table, you can do...

HtmlDom.select('table>tbody').append( NewRow )

...to just add the new row at the end.

Creating Objects From Jar Files

The above code most likely wont work instantly if you copy and paste it, because your server doesn't know about JSoup - you need to download the Jar file and put it in a sensible location.

For CF9, you need to copy the jsoup-1.6.3.jar into your {coldfusion}/lib directory then restart the server.

For CF10, you can use this.JavaSettings in your Application.cfc (as described here) to place it in a different location.

For Railo and OpenBD, you can specify the location of the JAR file as a third argument, e.g:

<cfset jsoup = createObject('java','org.jsoup.Jsoup','lib/jsoup-1.6.3.jar') />