Kennedy,
Thank you for trying Webclipse.
Please check this tutorial about content assist for JavaScript :
Using Content Assist for JavaScript with JSjet
Access to content assist for a large number of third-party framework libraries is available through project properties. When including third-party JavaScript frameworks like jQuery, you must either include the framework scripts within the project, or reference them on the web.
Right click on the project > Properties > JavaScript > Include Path. The Tern modules available on the Technologies tab offer predefined content assist for various technologies.
Please refer to the : Better Content Assist with Tern Modules section in the above tutorial for detailed steps.
Hope this helps. Let us know if you see any issues.
–Swapna
MyEclipse Support