Basic question.
document.getElementById("yy").onmouseover = hi; //document.getElementsByTagName("li").onmouseover = hi; ... In this example, http://jsfiddle.net/8fURz/1/ why does the first line work, but not the second line (when it is un-commented, of course)?
I know I can do this easily with jQuery, just wonderin...
Because document.getElementsByTagName("li") return a NodeList, you need to bind event handler to every element of the NodeList.
var list = document.getElementsByTagName("li"); for (var i= 0; i < list.length; i++) { list[i].onmouseover = hi; } Because getElementsByTagName returns a collection of DOM elements. Of course a collection doesn't have a click event. If you want to bind an event to every element in the collection, you would simply loop through the collection and add a handler to every DOM element in the collection.
.getElementsByTagName()returns an array of objects, while.getElementById()returns an object, so you have to select a specific index with the former, but not the latter (since it's single by nature).