VAST tracking events


#1

I am looking into VAST advertisement and I understand the implementation except on thing, there are the tracking URI’s that has to be executed, how exactly it is done with javascript, I could not find any reference about it for example below is an excerpt from a VAST XML file

<TrackingEvents>
          <Tracking event="midpoint"><![CDATA[http://example.com/linear-midpoint]]></Tracking>
          <Tracking event="complete"><![CDATA[http://example.com/linear-complete]]></Tracking>
          <Tracking event="start"><![CDATA[http://example.com/linear-start]]></Tracking>
          <Tracking event="firstQuartile"><![CDATA[http://example.com/linear-firstQuartile]]></Tracking>
          <Tracking event="close"><![CDATA[http://example.com/linear-close]]></Tracking>
          <Tracking event="thirdQuartile"><![CDATA[http://example.com/linear-thirdQuartile]]></Tracking>
          <Tracking event="progress" offset="00:00:30.000"><![CDATA[http://example.com/linear-progress-30sec]]></Tracking>
          <Tracking event="progress" offset="60%"><![CDATA[http://example.com/linear-progress-60%]]></Tracking>
        </TrackingEvents>

How exactly for example this URI “http://example.com/linear-midpoint” is executed with javascript. Any help is appreciated.

Thank you.