Can explain this block Code to me PHP XML DOMDocument Syntax -

I am currently learning different ways using XML document tags, using the php DOMDocument object, I Understand foreach to loop through the tag, but $ element-> Items (0) - & gt; Child nodes-> Items (0) - & gt; Node Vela is not quite clear Is anyone can tell me in detail? Thank you.

  & lt ;? Php $ xmlDoc = new DOMDocument (); $ XmlDoc- & gt; Load ('StudentData.xml'); $ StudentRoot = $ xmlDoc- & gt; GetElementsByTagName ('student'); ($ I = $; $ i & lt; ($ studentRoot- & gt; Length); $ i ++) {$ firstNameTags = $ studentRoot- & gt; Items ($ i) - & gt; GetElementsByTagName ('first name'); Echo $ First Name Tag- & gt; Items (0) - & gt; Child nodes-> Items (0) - & gt; Node vale '& Lt; Br / & gt; '; } / * So simple and clear to understand! * / Foreach ($ student $$ root as node) {/ * each & lt; Students & gt; Tag it as a separate node, move it into the child's node, and for each child, echo the text content * / foreach ($ node-> as childNodes $$) {echo $ child- & Gt; TextContent & Lt; Br / & gt; '; }}? & Gt;    
 
 
  $ element-> Items (0) - & gt; ChildNodes- & Gt; Items (0) - & gt;       
     / Strong>   In parse and referenced code example, this would be:  
  $ firstNameTags = $ studentRoot- & gt; Items ($ i) - & gt; GetElementsByTagName ('first name'); $ FirstNameTags-> ...   
 Next:  
  - & gt; A reference before item (0)   
 go  $ elements  because it is zero-indexed, so  ->  Index  <>  -> In the  list  in the  list  item (0)  ChildNodes   
 Get a list of  referenced by that  $ Elements  node> - & gt; Item (0)  above is not a  () , this is a (read only)  DOMNodeList   property .  
  Again, get the first node in the list of hair nodes by  index .  
  - & gt; Nodevela   
 by itself.  
 
 If the state is:  
  $ obj-> gt; Method () - & gt; Method () - & gt; Sahay   
 To tell you, check, which uses all the method to call simultaneously.  <     $   note, you have left  s , but this indicates That is one or more possible  by the conference . Then the  $ element   element will be zero or one , the  $ element  can be zero, one or more of the $ element in a collection of $ .