Added W3Schools resource about form validation (#3054)

content/roadmaps/100-frontend/content/101-html/102-forms-and-validations.md

@@ -5,3 +5,5 @@ Before submitting data to the server, it is important to ensure all required for
 <ResourceGroupTitle>Free Content</ResourceGroupTitle>
 <BadgeLink badgeText='Read' colorScheme='yellow' href='https://developer.mozilla.org/en-US/docs/Learn/Forms/Form_validation'>MDN Web Docs: Client-side form validation</BadgeLink>
 <BadgeLink badgeText='Read' colorScheme='yellow' href='https://web.dev/learn/forms/'>Learn Forms by web.dev</BadgeLink>
+<BadgeLink badgeText='Read' colorScheme='yellow' href='https://www.w3schools.com/js/js_validation.asp'>W3Schools: JavaScript Form Validation</BadgeLink>
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