For example:
Id = plcRoot_Layout_zoneMainLayout_pageplaceholder1_partPlaceholder_Layout_zoneMainContent
_pageplaceholder_partPlaceholder_Layout_zonePageContent_pageplaceholder_partPlaceholder
_Layout_zoneContent_SearchOptions_ctl00_SearchCriteria_CommonOptions_MyField
The long names are product of ASP.NET. It involves all parents IDs to ensure the unique names of controls. We would not recommend changing of it.
If you would really need it these articles could help you:
www.west-wind.com/WebLog/posts/4605.aspx
michaelcodes.net/post/ASPNET-WebControl-ClientID-Bloat.aspx