选中ASP.NET Gridview中的所有复选框，同一页面上的多个表

Alright, so there is tons of documentation out there that I have filed through and attempted many times throughout the day and can not seem to nail this issue down. I have multiple Gridviews on one page (inside of collapsible panels), of which two have a column (the 7th column, from 0) that contains checkboxes. I want to enable the user to select/deselect all of the checkboxes using a checkbox field in the header row. I prefer to accomplish this using Javascript, but can't seem to be able to get there. Alright, so there is tons of documentation out