Prototype: Invoke Click Select Parent Attribute
$$('.delete').invoke('observe', 'click', function() {
var attr = $(this).up().readAttribute('id');
$(this).toggleClassName('red');
console.log(attr);
});
<ul>
<li id='item_1'>Item MNO <span class='delete'>DELETE</span></li>
<li id='item_2'>Item PQR <span class='delete'>DELETE</span></li>
<li id='item_0'>Item XYZ <span class='delete'>DELETE</span></li>
</ul>