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Current time:0:00Total duration:2:20

Video transcript

on Khan Academy we pop up the Ono's guide to tell you when there's something wrong with your webpage but we only tell you about the big things there could be other things wrong with your webpage two things that aren't quite right according to the HTML specification but the browser's let you get away with it because browsers like to be really forgiving they just want to make it work and so then you end up not knowing that there's something wrong with your webpage that's why it's a good idea to run your web page through the w3 validation service and that will actually check and tell you if your page is valid and if there's something not quite right about it to do that go to validator w3.org it'll give you options to enter a URL upload a file or just copy and paste and that's what I'll do I'll take the most recent web page that I was showing in a talk through and paste it in here and then check tada it was successfully checked as html5 and there were no issues with it fantastic let's try one more this is our HTML internal links example I'm going to paste this in here and check oh there was one error two warnings let's go down it says that an image element must have an alt attribute oh this is a classic thing to forget is that alt attribute please we see the images but not everybody does so what I should do is go back into that HTML and add the alt attribute so let's say the image was here alt equals photo of Tim berners-lee next to computer and let me copy and go back up paste and I will revalidate tada it's valid HTML when possible you should be trying to make web pages that are valid HTML because that way you can have a lot more confidence that the browser is going to interpret them exactly like you expect all the time now go try and validate a few of your pages and see how they turn out