List of rules
Possible errors
Doctype and Head
doctype-first: Doctype must be declared first.doctype-html5: Invalid doctype.html-lang-require: The HTML lang attribute is required.head-script-disabled: The<script>tag cannot be used in a tag.style-disabled:<style>tags cannot be used.script-disabled:<script>tags cannot be used.title-require:<title>must be present in<head>tag.
Attributes
attr-lowercase: All attribute names must be in lowercase.attr-no-duplication: Elements cannot have duplicate attributes.attr-no-unnecessary-whitespace: No spaces between attribute names and values.attr-unsafe-chars: Attribute values cannot contain unsafe chars.attr-value-double-quotes: Attribute values must be in double quotes.attr-value-single-quotes: Attribute values must be in single quotes.attr-value-not-empty: All attributes must have values.attr-sorted: Attributes should be sorted in order.attr-whitespace: No leading or trailing spaces in attribute values.alt-require: The alt attribute of an element must be present and alt attribute of area[href] and input[type=image] must have a value.input-requires-label: All [ input ] tags must have a corresponding [ label ] tag.
Tags
tags-check: Allowing specify rules for any tag and validate thattag-pair: Tag must be paired.tag-self-close: Empty tags must be self closed.tagname-lowercase: All html element names must be in lowercase.tagname-specialchars: Tag names can only contain letters, numbers, "-", ":" or "_".empty-tag-not-self-closed: The empty tag should not be closed by self.src-not-empty: The src attribute of an img(script,link) must have a value.href-abs-or-rel: An href attribute must be either absolute or relative.
Id
id-class-ad-disabled: The id and class attributes cannot use the ad keyword, it will be blocked by adblock software.id-class-value: The id and class attribute values must meet the specified rules.id-unique: The value of id attributes must be unique.
Inline
inline-script-disabled: Inline script cannot be used.inline-style-disabled: Inline style cannot be used.
Formatting
space-tab-mixed-disabled: Do not mix tabs and spaces for indentation.spec-char-escape: Special characters must be escaped.