This demo uses ESRI's elevation service and Highcharts, to create very cool elevation profiles.
Note that some of the trails are very long and may not process quickly.

Basemap is provided by ESRI
Trails data by Pitkin County, Colorado

References:

• http://sampleserver6.arcgisonline.com/arcgis/rest/services/Elevation/WorldElevations/MapServer/exts/ElevationsSOE_NET/ElevationLayers/0
• http://www.arcgis.com/apps/OnePane/basicviewer/profile.html?appid=13a3167e95134cdda5277c0b47fcd626
• http://www.arcgis.com/apps/ElevationsProfile/index.html