Getting meta tag on a web page

Get Meta Tags .js

function getMetaTags() { 
   var metas = document.getElementsByTagName('meta');

   var ogMetasKey = "og:";

   for(var i = 0; i < metas.length; i++){
   	if(metas[i] !== undefined){
   		var currentMeta = metas[i];
	   		if(currentMeta.getAttribute('property') !== null && currentMeta.getAttribute('content') !== null){
	   			if(currentMeta.getAttribute('property').indexOf(ogMetasKey) !== -1) {
	   				console.log(currentMeta.getAttribute('property'), currentMeta.getAttribute('content'));
	   			}
	   		}
   		}
   	}
}