what is the difference between getelementsbytagname and getelementsbyname in javascript -

i came across these 2 methods dom elements retrieval in douglas crockford presentation couldn't understand difference between these two.

document.getelementsbytagname()  document.getelementsbyname() 

can please explain me.

the link video http://www.youtube.com/watch?v=fv9qt9joc0m

suppose have html :

<input name="test" class="cssclassname"> 

you'd got with

document.getelementsbytagname('input') 

or

document.getelementsbyname('test') 

or

document.getelementsbyclassname('cssclassname') 

also, can call getelementsbytagname on elements other document. example following allowed,

document.getelementsbyid('foo').getelementsbytagname('bar') 

but getelementsbyname can called on document.

notes :

• javascript case sensitive, can't write functions did in question
• those functions don't return element live nodelist, you'll have iterate on result or take first 1 if you're sure it's : document.getelementsbytagname('input')[0]
• the mdn documentation javascript methods. should read getelementsbytagname , getelementsbyname.