For example for this.parentNode I would like to just write this.p or instead of
document.getElementById(\'someid\') just write d
Although you can prototype on the HTMLElement in many browsers - Internet Explorer (6,7,8) is NOT one of them. AFAIK, IE9 does support this (though I haven't tested it).
For browsers that do handle it, you can do:
HTMLElement.prototype.doHello = function(thing){
alert('Hello World from ' + thing);
};