function ogSetTitle(title) {
	ogSetProperty("og:title", title);
}

function ogSetType(type) { // activity|article|website|blog  : http://developers.facebook.com/docs/opengraph/#types
	ogSetProperty("og:type", type);
}

function ogSetUrl(url) {
	ogSetProperty("og:url", url);
}

function ogSetImg(img) {
	ogSetProperty("og:image", img);
}

function ogSetSitename(sitename) {
	ogSetProperty("og:site_name", sitename);
}

function ogSetProperty(prop, val) {
 metatags = document.getElementsByTagName("meta");
 for (i = 0; i < metatags.length; i++)
 {
	var property = metatags[i].getAttribute("property");
	if(property == prop) {
		metatags[i].setAttribute("content", val);
	}
 }
}