how to reference the id of my checkbox in a dynamic GridView control

In my C# code I am creating a dynamic GridView control and one of the columns is a check box. In my C# code I am also assigning an ID to my
check box control in my RowDataBound event.  ===>   chkBox.ID = "CheckBox" + e.Row.RowIndex


However when my page is rendered, the id of the checkbox is prepended with the text "MainContent_myGrid_"  and appended by and underscore and then the number.
Example

<input id = "MainContent_myGrid_CheckBox3_3" type="checkBox" name="ctl00$MainContent$myGrid$ct103>


I want to be able to disable the checkbox using Java script.How can I reference the check box control by the ID I assigned to it in the GridView control?
Is there a way to do it, without having to reference the prepended "MainContent_myGrid_" text and the appended text of underscore followed by the number
of the check box?