I tried to use RoboB and got as far as I could but unfortunately when I tried to extract the data in the html the value is a variable that is pulled in at runtime.
It's hard to know the right course of action without seeing the page you're talking about and the command you've been using, but an important tool when using RoboB is the RoboB.Wait action. This usually allows even dynamic pages to finish loading all their content before we grab anything from that page.
Below is an example to illustrate the point, using Google's online calculator.
Test the command with the RoboB.Wait action disabled (as it is now), then test it with the action enabled. The command only works in the latter instance.
<?xml version="1.0" encoding="utf-16"?>
<!--VoxCommando 2.1.3.3-->
<command id="425" name="RoboB.Wait Test" enabled="true" alwaysOn="False" confirm="False" requiredConfidence="0" loop="False" loopDelay="0" loopMax="0" description="Test this command several times, changing the RoboB.Wait repeat value from "0" (0 = disabled action) to the standard "1". Calculation only works if we wait for the page to finish loading.">
<action>
<cmdType>RoboB.Select</cmdType>
<params>
<param>ggTest</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>RoboB.Navigate</cmdType>
<params>
<param>https://www.google.ca/search?q=calculate+{1}*{2}</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>RoboB.Wait</cmdType>
<params />
<cmdRepeat>0</cmdRepeat>
</action>
<action>
<cmdType>RoboB.Show</cmdType>
<params />
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>RoboB.ElementByID</cmdType>
<params>
<param>cwos</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>RoboB.GetText</cmdType>
<params />
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>OSD.ShowText</cmdType>
<params>
<param>{LastResult}</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>TTS.Speak</cmdType>
<params>
<param>{LastResult}</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<phrase>calculate</phrase>
<payloadRange>1,10</payloadRange>
<phrase>times</phrase>
<payloadRange>1,10</payloadRange>
</command>