Add onclick event programmatically to listitems
How to Catch the OnClick Event of SharePoint List Item
For example, you can programmatically add handlerFunction as an onclick event handler for an element by using these methods: element.attachEvent('onclick',handlerFunction); (in Internet Explorer 5 or …... However, if you programmatically change the Checked property, the OnClick event will be fired-- even though no user interaction took place. There are (at least) two ways to programmatically change the checked property of the checkbox while "disabling" the OnClick event.