Getting DOM elements by classname

Question

I m using PHP DOM and I m trying to get an element within a DOM node that have a given class name   What s the best way to get that sub-element   Update  I ended up using Mechanize for PHP which was much easier to work with

User · Answer

DOMDocument is slow to type and phpQuery has bad memory leak issues  I ended up using   https   github com wasinger htmlpagedom  To select a class   include  includes simple html dom php     doc   str get html  html    href    doc- gt find   lastPage   0 - gt href    I hope this helps someone else as well

User · Answer

Update  Xpath version of    class   my-class   css selector So after my comment below in response to hakre s comment  I got curious and looked into the code behind Zend Dom Query  It looks like the above selector is compiled to the following xpath  untested    contains concat      normalize-space  class           my-class     So the PHP would be   dom   new DomDocument     dom- gt load  filePath    finder   new DomXPath  dom    classname  quot my-class quot    nodes    finder- gt query  quot     contains concat      normalize-space  class            classname     quot     Basically  all we do here is normalize the class attribute so that even a single class is bounded by spaces  and the complete class list is bounded in spaces  Then append the class we are searching for with a space  This way we are effectively looking for and find only instances of my-class    Use an xpath selector   dom   new DomDocument     dom- gt load  filePath    finder   new DomXPath  dom    classname  quot my-class quot    nodes    finder- gt query  quot     contains  class    classname    quot     If it is only ever one type of element you can replace the   with the particular tagname  If you need to do a lot of this with very complex selector I would recommend Zend Dom Query which supports CSS selector syntax  a la jQuery    finder   new Zend Dom Query  html    classname    my-class    nodes    finder- gt query  quot   class    quot  classname  quot   quot

User · Answer

I prefer using Symfony for this  Their libraries are pretty nice  Use the The DomCrawler Component Example   browser   new HttpBrowser HttpClient  create      crawler    browser- gt request  GET    example com     class    crawler- gt filter   class  - gt first

User · Answer

If you wish to get the innerhtml of the class without the zend you could use this    dom   new DomDocument     dom- gt load  filePath    classname    main-article    finder   new DomXPath  dom    nodes    finder- gt query      contains concat      normalize-space  class            classname         tmp dom   new DOMDocument     foreach   nodes as  node              tmp dom- gt appendChild  tmp dom- gt importNode  node true           innerHTML  trim  tmp dom- gt saveHTML      echo  innerHTML

User · Answer

I think the accepted way is better  but I guess this might work as well  function getElementByClass  amp  parentNode   tagName   className   offset   0         response   false        childNodeList    parentNode- gt getElementsByTagName  tagName        tagCount   0      for   i   0   i  lt   childNodeList- gt length   i               temp    childNodeList- gt item  i           if  stripos  temp- gt getAttribute  class     className      false                if   tagCount     offset                     response    temp                  break                              tagCount                          return  response

User · Answer

There is also another approach without the use of DomXPath or Zend Dom Query   Based on dav s original function  I wrote the following function that returns all the children of the parent node whose tag and class match the parameters   function getElementsByClass  amp  parentNode   tagName   className         nodes array          childNodeList    parentNode- gt getElementsByTagName  tagName       for   i   0   i  lt   childNodeList- gt length   i               temp    childNodeList- gt item  i           if  stripos  temp- gt getAttribute  class     className      false                 nodes    temp                       return  nodes      suppose you have a variable  html the following HTML    lt html gt    lt body gt     lt div id  content node  gt       lt p class  a  gt I am in the content node  lt  p gt       lt p class  a  gt I am in the content node  lt  p gt       lt p class  a  gt I am in the content node  lt  p gt         lt  div gt     lt div id  footer node  gt       lt p class  a  gt I am in the footer node  lt  p gt     lt  div gt    lt  body gt   lt  html gt    use of getElementsByClass is as simple as    dom   new DOMDocument  1 0    utf-8     dom- gt loadHTML  html    content node  dom- gt getElementById  content node      div a class nodes getElementsByClass  content node   div    a     will contain the three nodes under  content node

[php] Getting DOM elements by classname

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