how to change map directions service travel mode in javascript code example

Example: javascript link to google maps route

//https://www.google.com/maps/dir/?api=1&parameters


//The following example launches a map with bicycling directions from the Space Needle to Pike Place Market, in Seattle, WA.

//https://www.google.com/maps/dir/?api=1&origin=Space+Needle+Seattle+WA&destination=Pike+Place+Market+Seattle+WA&travelmode=bicycling