angular ng-keydown not working on safari checkboxes

In our Angular app, I'm trying to implement shift select on a bunch of rows in a table using a checkbox in the first column. The checkboxes register the shift click using the ng-keydown handler. On Chrome this seems to work fine, but in Safari the checkboxes don't acknowledge the keydown event. After a little experimentation, I see that keydown is registered with text inputs on Safari, but does not work for checkboxes. Is there an alternate way to get shfit-click to work for Safari checkboxes?