如何使用html dom获取javascript中的复选框cheked值

Basically i have a list of checkbox which the data are retrieved from database and i stored it in vector to loop it. Now I need to get the value those are selected(checked) and bring it to another jsp for some purpose, may i know how can i make it ? i get "undefined" value when i alert in javascript. Any help would be appreciated. ThanksBasically i have a list of checkbox which the d