1. function validateHTML(html) {
  2. try {
  3. // Create a DOMParser to parse the HTML string
  4. const parser = new DOMParser();
  5. const doc = parser.parseFromString(html, 'text/html');
  7. // Check for required elements and attributes with default values
  8. if (!doc.querySelector('html')) {
  9. console.error('Error: Missing <html> element.');
  10. return { errors: ['Missing <html> element'] };
  11. }
  13. const htmlElement = doc.querySelector('html');
  14. if (!htmlElement.lang) {
  15. htmlElement.lang = 'en'; // Set default language
  16. }
  18. if (!doc.querySelector('head')) {
  19. console.warn('Warning: Missing <head> element. Defaulting to empty <head>.');
  20. }
  22. const headElement = doc.querySelector('head');
  23. if (!headElement.title) {
  24. headElement.title = 'Default Title'; // Set default title
  25. }
  27. if (!doc.querySelector('body')) {
  28. console.error('Error: Missing <body> element.');
  29. return { errors: ['Missing <body> element'] };
  30. }
  32. const bodyElement = doc.querySelector('body');
  33. if (!bodyElement.style) {
  34. bodyElement.style = {}; // Ensure style attribute exists
  35. }
  37. if (!bodyElement.style.fontFamily) {
  38. bodyElement.style.fontFamily = 'sans-serif'; // Set default font-family
  39. }
  41. if (!bodyElement.style.margin) {
  42. bodyElement.style.margin = '0'; // Set default margin
  43. }
  45. // Check for common missing elements (expand as needed)
  46. if (!doc.querySelector('title')) {
  47. console.warn('Warning: Missing <title> element. Defaulting to empty <title>.');
  48. }
  49. const titleElement = doc.querySelector('title');
  50. if (!titleElement) {
  51. titleElement = doc.createElement('title');
  52. headElement.appendChild(titleElement);
  53. titleElement.textContent = 'Default Title';
  54. }
  56. return { errors: [] }; // No errors found
  57. } catch (e) {
  58. console.error('Error parsing HTML:', e);
  59. return { errors: ['HTML parsing error'] };
  60. }
  61. }
  63. // Example Usage (replace with your HTML string)
  64. // const htmlString = '<html lang=""><body><div>Hello</div></body></html>';
  65. // const validationResult = validateHTML(htmlString);
  66. // if (validationResult.errors.length > 0) {
  67. // console.error('Validation Errors:', validationResult.errors);
  68. // } else {
  69. // console.log('HTML is valid (with default values)');
  70. // }

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