passing simple search result as token to chart searchstring without any input in a form using simple xml

I have a search query which results the top 1 value from a field called "eventtype" and this top 1 value will change time to time since my dashboard is refreshing for every 1 minute.Now I want to pass this top 1 value as a token to my chart searchstring.means I want to run a search automatically when form is loading and passing the searchresult as token Can we do this one using simple xml.