Difference between block’s “name” and “as” attributes in layout XML?

Question

what is the Difference between id and name attributes in HTML?

Answer 1

here i can give brief understanding regarding magento block xml tag

name = Name of the block. It should be unique in the page.

*as = Alias *. Smaller form of name. It should be unique in it's parent block.

template = The template file (View) this block is attached to.

You can call methods from block type inside this by using $this.. e.g. $this->getName()

name vs. as example:

<reference name="left">
    <block type="block/blocktype1" name="first_block" template="template1.phtml">
       <block type="abc/abc" name="ty1" as="common" template="abc.phtml"/> 
    </block>
    <block type="block/blocktype1" name="second_block" template="template2.phtml">
       <block type="xyz/xyz" name="ty2" as="common" template="xyz.phtml"/>            
    </block>
</reference>

So, we can now call block name ty1 from first_block AND ty2 from second_block as $this->getChildHtml('common');, but see both the blocks called will be different as per their calling parent.