getElementById returns null

Question

document getElementById  id of div that definately exists   returns null   I originally loaded the javascript last in order to make sure I wouldn t need to worry about the onload event  I also tried using the onload event  It s very spooky  Any ideas or help would be greatly appreciated

User · Answer

There could be many reason why document getElementById doesn t work   You have an invalid ID      ID and NAME tokens must begin with a letter   A-Za-z   and may be followed by any number of letters  digits   0-9    hyphens   -    underscores        colons        and periods           resource  What are valid values for the id attribute in HTML    you used some id that you already used as  lt meta gt  name in your header  e g  copyright  author      it looks weird but happened to me  if your  re using IE take a look at  resource  http   www phpied com getelementbyid-description-in-ie   you re targeting an element inside a frame or iframe  In this case if the iframe loads a page within the same domain of the parent you should target the contentdocument before looking for the element  resource  Calling a specific id inside a frame  you re simply looking to an element when the node is not effectively loaded in the DOM  or maybe it s a simple misspelling   I doubt you used same ID twice or more  in that case document getElementById should return at least the first element

User · Answer

Also be careful how you execute the js on the page  For example if you do something like this    function window  document  undefined      var foo   document getElementById  foo       console log foo       window  document  undefined      This will return null because you d be calling the document before it was loaded   Better option     function window  document  undefined       code that should be taken care of right away  window onload   init     function init           the code to be called when the dom has loaded         document has its nodes         window  document  undefined

User · Answer

It can be caused by    Invalid HTML syntax  some tag is not closed or similar error  Duplicate IDs - there are two HTML DOM elements with the same ID Maybe element you are trying to get by ID is created dynamically  loaded by ajax or created by script     Please  post your code

[javascript] getElementById returns null?

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