WordPress Custom HTML Widget Error – The attribute name must be in lowercase
Many people want’t to add their customized HTML code from third parties like SEO, Affliates and many more. Coder or Blogger or Developer must place the code without any changes.
The code is generated by the affiliate program. Programmer don’t want to alter the code in case they come back and say you not eligible for payment because the developer altered their code
Who is the Provider?
The custom HTML Widget is provided by WordPress and it works with predefined settings . Updating the WordPress can not help.
Where the file is Located?
The file is located under wp-includes folder .
How to fix it ?
Just changing the htmlhint settings attr-lowercase, you can set the following settings to disable it.
'htmlhint' => array('attr-lowercase' => false);
Including all properties.
'htmlhint' => array(
'tagname-lowercase' => true,
'attr-lowercase' => false, // Allows all characters
//'attr-lowercase' => true, it allows only lowercase
'attr-value-double-quotes' => false,
'doctype-first' => false,
'tag-pair' => true,
'spec-char-escape' => true,
'id-unique' => true,
'src-not-empty' => true,
'attr-no-duplication' => true,
'alt-require' => true,
'space-tab-mixed-disabled' => 'tab',
'attr-unsafe-chars' => true,