ajax editing fails for Safari / #4113

replaced...

from misc.js

    if(dom_element.attributes['item_id']) {
        item_id= dom_element.attributes['item_id'].value;
    }

with...

from misc.js

    if($(dom_element).attr('item_id')) {
        item_id= $(dom_element).attr('item_id');
    }
    else {
        alert("Warning: no item id for ajax editing!");
        return;
    }

I have no idea why the querying for custom DOM attributes fails with the first version, though.