How to get the attributes of a tag of XML in PHP

[Mushroom]

I do not clear about the functions of XML.
There are some global vars when parsing XML,such as $name,$args,$attrs.
But where do they come from ?and How to use them ?
I have tried $attrs which is a string.But no use.I suppose it should be an array if the tag have several attributes.

Need help!

[Weedpacket]

According to the manual, the third argument to the function named by [man]xml_set_element_handler[/man] ($attribs) is an array. That's the closest I can come to figuring out what you're talking about. If you're getting a string, what does it contain?

[Mushroom]

its empty