Is Element.tagName always uppercase?

by

You don’t have to toLowerCase or whatever, browsers do behave the same on this point (surprisingly huh?).

About the rationale, once I had discussion with a colleague who’s very professional on W3C standards. One of his opinions is that using uppercase TAGNAME would be much easier to recognize them out of user content. That’s quite persuasive for me.

Edit: As @adjenks says, XHTML doctype returns mixed-case tagName if the document is served as Content-Type: application/xhtml+xml. Test page: http://programming.enthuses.me/tag-node-case.php?doc=x

Technically, please read this spec for more info: http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-745549614

Note that this (tagName) is case-preserving in XML, as are all of the operations of the DOM. The HTML DOM returns the tagName of an HTML element in the canonical uppercase form, regardless of the case in the source HTML document.

As of asker’s question: this is trustable. Breaking change is not likely to happen in HTML spec.

Related Contents:

  1. React-router URLs don’t work when refreshing or writing manually
  2. Formatting a number with exactly two decimals in JavaScript
  3. orderBy multiple fields in Angular
  4. Why doesn’t indexOf work on an array IE8?
  5. Do something if screen width is less than 960 px
  6. What’s the purpose of prototype? [duplicate]
  7. toBe(true) vs toBeTruthy() vs toBeTrue()
  8. Moment js get first and last day of current month
  9. Removing event listener which was added with bind
  10. lodash multi-column sortBy
  11. Read a text file using Node.js?
  12. How to check if element has any children in Javascript?
  13. How to add text inside the doughnut chart using Chart.js?
  14. catch forEach last iteration
  15. flatMap, mergeMap, switchMap and concatMap in rxjs?
  16. How do I get first element rather than using [0] in jQuery?
  17. Removing object properties with Lodash
  18. javascript filter array of objects
  19. JavaScript: Round to a number of decimal places, but strip extra zeros
  20. Node js Error: Protocol “https:” not supported. Expected “http:”
  21. how to make twitter bootstrap submenu to open on the left side?
  22. How to get background image URL of an element using JavaScript?
  23. Confused about useBuiltIns option of @babel/preset-env (using Browserslist Integration)
  24. Does scrollIntoView work in all browsers?
  25. HTTP Authorization Header in EventSource (Server Sent Events)
  26. Getting an absolute URL from a relative one. (IE6 issue)
  27. How to check if the input string is a valid Regular expression?
  28. Executing JavaScript after X seconds
  29. When to use Requirejs and when to use bundled javascript?
  30. how to parse a “dd/mm/yyyy” or “dd-mm-yyyy” or “dd-mmm-yyyy” formatted date string using JavaScript or jQuery [duplicate]
  31. prevent Scroll bubbling from element to window
  32. Any way to throttle calls to a specific API in Chrome DevTools while leaving others unthrottled?
  33. Why is the execution time of this function call changing?
  34. Chrome Extension – How to get HTTP Response Body?
  35. How to run user-submitted scripts securely in a node.js sandbox?
  36. Updating a Nested Array with MongoDB
  37. Hide select option in IE using jQuery
  38. Refer to javascript function from within itself
  39. What is minimum millisecond value of setTimeout?
  40. Alerts when navigating away from a web page
  41. Wrapping Text lines in JqGrid
  42. How to replace a substring between two indices
  43. check if user has already installed PWA to homescreen on Chrome?
  44. How to add content to html body using JS?
  45. Resharper, Javascript: “Use of implicitly declared global variable ‘X'”
  46. For a push notification, is a websocket mandatory?
  47. HTML form action and onsubmit issues
  48. Issues with Date() when using JSON.stringify() and JSON.parse()
  49. jQuery sort elements using data id
  50. How to change AngularJS data outside the scope?

Leave a Comment