function createAnElement(type,namevalue,contentvalue,src){
	var newElement = document.createElement(type);
	if (type == 'meta') {
		newElement.name = namevalue;
		newElement.content = contentvalue;
	}
	if (type == 'link') {
		newElement.rel = "image_src" ;
		newElement.href = src;
	}
    document.getElementsByTagName('head')[0].appendChild(newElement);
}
function ifAPost(id){
	var thePost = document.getElementById("post_" + id);
	var posttitle = document.getElementById("title_" + id).innerHTML;
	var postcontent = document.getElementById("content_" + id).innerHTML;
	createAnElement('meta','title',posttitle,'');
	createAnElement('meta','description',postcontent,'');
}
function ifnoPost(){
	var posttitle = "Le blog de Sailortoshyo";
	var postcontent = "C'est le blog d'un pédé de - de 30 ans, parisien (ou presque), un peu fou, et qui écrit depuis longtemps.";
	var image = "http://www.sailortoshyo.com/images/site/2011/grey/sailortoshyo.jpg";
	createAnElement('meta','title',posttitle,'');
	createAnElement('meta','description',postcontent,'');
	createAnElement('link','','',image);
}