Add a hyperlink to work notes / activity trail

 see 

https://www.servicenowguru.com/scripting/script-includes-scripting/attach-knowledge-link/

use this within the a tag to make it clickable from the activity trail:

sURL=this.instance_url+ "nav_to.do?uri=pa_dashboards_list.do?sysparm_query=owner%3D" + this.usersysid;

sMsg+='URL: [code]<a target="_blank" href="' + sURL + '">';

sMsg+=sURL;

sMsg+='</a>[/code]';

sMsg+='\n';

See this UI action script example:

//--write to activity trail

var sNum='INC0010008';

var instance_url=gs.getProperty('glide.servlet.uri'); //gs.getProperty('instance_name');

//gs.addInfoMessage(instance_url);

var sMsg='';

var sURL=instance_url+ "nav_to.do?uri=incident_list.do?sysparm_query=number%3D" + sNum;

sMsg+='URL: [code]<a target="_blank" href="' + sURL + '">';

sMsg+=sURL;

sMsg+='</a>[/code]';

sMsg+='\n';

//gs.addInfoMessage(sMsg);

current.work_notes=sMsg;

current.update();

action.setRedirectURL(current);