ECMAScript to read Hyperlink URL and description

var context = SP.ClientContext.get_current();

var myListItem = context.get_web().get_lists().getByTitle("ListName").getItemById(1);

context.load(myListItem);

context.executeQueryAsync(

function()

{
    /* On Success */

    alert(myListItem.get_item("HyperLinkFieldName").get_description());

    alert(myListItem.get_item("HyperLinkFieldName").get_url());

},

function(sender,args)

{
    /* On Failure */

   alert(args.get_message());

}

);