mailto link (in chrome) is triggering window.onbeforeunload - can i prevent this?

Add a flag and see if it is flipped, set the flag on the link click.

var ignore = false
window.onbeforeunload = function() {
    if (changed && !ignore) {
        return "You have unsaved changes.  Do you really want to leave this page without saving?";
    } else {
        ignore = false;
    }
}

And the link

<a class="button button-alt" href="mailto:[email protected]" onclick="ignore=true">Report a problem</a>

It would be better to add the onclick with JavaScript code.

Building off of epascarello's solution, the following JQuery code should do the trick:

    var ignore_onbeforeunload = false;
    $('a[href^=mailto]').on('click',function(){
        ignore_onbeforeunload = true;
    });

    window.onbeforeunload = function() {
        if (!ignore_onbeforeunload){
            return "Halt! you are not supposed to leave!";
        }
        ignore_onbeforeunload = false;
    };

A really simple fix to this is to do something like this:

<a href="mailto:[email protected]" target="hidden-iframe">Email me</a>
<iframe name="hidden-iframe" style="visibility:hidden;position:absolute;"></iframe>

(And of course, move the styles to their own stylesheet instead of inlining them.)