Common XHTML Validation error 

  Original: http://www.blackwidows.org.uk/resources/tutorials/xhtml/common-errors.html 

  Without coding and symbols ("&") 

  Example: 
  <a Href="foo.cgi?chapter=1&section=2"> ...</ a> 

  Could lead to verify reports: unknown entity ... 

  Solution: Always & & alternative. 

  Correct grammar: 
  <a Href="foo.cgi?chapter=1&section=2"> ...</ a> 

  Wrong nested elements 

  Example: 
  <strong> <em> ...</ Strong> </ em> 

  Could lead to verify reports: loss of </ em> Tags 

  Solution: XHTML in all the elements must be in accordance with its open closure order to the contrary. 

  Correct grammar: 
  <strong> <em> ...</ Em> </ strong> 

  Lowercase the DOCTYPE 

  Example: 
  <! Doctype html public "- / / w3c / / dtd xhtml 1.0 strict / / en" 
  "Http://www.w3.org/tr/xhtml1/dtd/xhtml1-strict.dtd"> 

  Could lead to verify reports: lost DOCTYPE 

  Solution: DOCTYPE case sensitive, please use the correct spelling manner. 

  Correct grammar:: 
  <DOCTYPE html PUBLIC "- / / W3C / / DTD XHTML 1.0 Strict / / EN" 
  "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 

  Close loss "/" 

  Example: 
  <img Src="image.gif" width="100" height="100" alt="Logo"> 

  Could lead to verify reports: lost Close Tags 

  Solution: often referred to as "empty element", for example, img, and must add a space followed by a slash "/." 
  See XHTML Elements to view a complete list. 

  Correct grammar:: 
  <img Src="image.gif" width="100" height="100" alt="Logo" /> 

  Uppercase labels 

  Example: 
  <STRONG> <EM> ...</ EM> </ STRONG> 

  Could lead to verify reports: there was no specific Element ... 

  Solution: for all HTML elements and attributes names to use lowercase.    This is necessary because XML is case-sensitive.    For example, <em EM> and <> is different labels. 

  Correct grammar:: 
  <strong> <em> ...</ Em> </ strong> 

  No use enclosed in quotation marks attribute value 

  Example: 
  <td Rowspan=3> 

  Could lead to verify the report: the lack of "" 

  Solution: all the attribute value must be included, including those who appear to be digital value. 

  Correct grammar:: 
  <td Rowspan="3"> 

  The translator continued: 

  XHTML Strict documents used in the performance of certain tags or attributes 

  Example: 
  <a Href="#" target="_blank"> 

  Could lead to verify reports: this version of the HTML in the absence of the attributes 

  Solution: strict compliance with the definition of DTD writing code, or other documentation for your choice of an appropriate DOCTYPE.    Javascript can also + DOM to achieve certain results. 

  Correct grammar:: 
  <a Href="#" onclick="window.open(this.href);return false">