why is this code showing uncaught TypeError.please help..

Question

var x;
function magic(y)
{
x=document.getElementByTagName("img");
x.src="https://lh5.googleusercontent.com/proxy/pPBeGLABiPXS8S1_98koFm4JqKrID44cxA0hPbiwqdSe_TUf_UvQ_UCcPatnVSRWagFkp0p0qpiwy_C6lS7MSxKZEiibU6LNrZHEl6ppk_Lxw57TziCTsRkeYCOt4oFgXfmmglnXiACa3KsTyrihOkx2dvg7FxiCCpUWCQ3KZMVYatPj2rGXIIA=w368-h399-nc";
}

Answer 1

getElement "s" ByTagName("img")[0]