Get tag by rel attribute

getElementByRel.js

function getElementByRel(rel) {
    aElements = document.getElementsByTagName("link");
    relElems = [];
    for (i = 0; i < aElements.length; i++) {
        if (aElements[i].hasAttribute("rel") && aElements[i].rel == rel) {
             return aElements[i];
        }
    }
}

tag = getElementByRel('author');

alert(tag.href);