从依赖下拉列表中删除id的选项？

I'm trying to ged rid of some options in a dropdown (selectB) depending on the selection chosen in another dropdown (selectA). Unfortunately my solution doesn'n work. Does anyone have a hint? a132 is an option given in the first dropdown. If this option is being chosen the options b01 and b03 should be removed from the second dropdown. getridofoptions() is called onChange. bo2, bo4, b05 and b06 should stay in the dropdown. If the user alters the selection in the first dropdown, all possible options should be reactivated (don't have a glue how to do so). After this the getridofoptions should remove the options according to the new selection. Example: If selectA is bening changed from a132 to a133 the options b01, b02 und b04 should be kicked of and b03, b05, b06 should stay. Tankful for any support/ideas GeorgI'm trying to ged rid of some options in a drop