Newly added CSS rules are not working, but old CSS rules are

Question

I can't figure out this issue and I have tried looking this up and it is hard to find any one with this scenario. I am using a master page with two content pages. The first content page is default.aspx, of course. The master page has a png that is a banner. This has a rule that makes it responsive in a separate CSS file. This works fine.

For the first content page, I have three buttons that are styled using CSS ( they are custom buttons I made in a vector graphics program that change appearance when they are pressed, all using CSS ) and they are responsive. There is also a listbox that is styled and responsive with CSS.

The layout of the default page is like this: Two div containers: one that floats left and one that floats right. CSS is used to make these containers responsive. In the right div, I have my buttons and they are enclosed in their own divs. So .. and so on. Of course, the listbox is handled the same way with a div that encloses that as well.

Moving on to the second page, I have the same basic structure as the default page. My intention is to have in the right div an image, followed by a text box, then an image, and a text box. The left div will contain the same content that the default page has.

At this point, I have added to the second content page the list box and the CSS is working as expected. The list box looks just like it did on the default page and is responsive as well. So the CSS is working. For the first image, I need a new CSS rule. So I go to my CSS rule and add a new rule .image{ width: 100%; height: auto; } and then I add my image and set it up with the class reference and the image. It does not work. This image is in it's own div. If I change the class of the image to another class that was created previously, the image is responsive. So I can use the banner CSS rule and the image is responsive, I can use the button CSS rules and the image is responsive, it behaves like a button ( clicking on it makes it change its appearance, that kind of thing ), I can even add the rules for the list box and the image is responsive. If I then go back and try to use the rule for image, it doesn't work anymore.

Any ideas on what is going on. It is not making any sense what so ever. I added the rule to the CSS file just like I did with all the other rules but for some reason, this rule is not working at all.

Thank you guys for any help. I can post code if you guys need it, but I don't see how that would help. My image for the second content page is identical to how I did the banner and the rules for the banner and the image are virtually identical, except percentages are different. This is just super weird.

Answer 1

To improve the performance, browsers save the css files in their cache and use their cache. If they don't do that, the browser has to keep loading the css file every time a page is using the css file.

If you clear your browser cache, you will notice that the new style gets applied.

If you are developing commercial software, you probably don't want to tell every user to clear their browser cache and you prefer to force the browser to load the new css file. On the other hand, once the css is loaded you would like the browser to cache it, because it will improve the performance.

There is a trick to achieve that!

Let's say your style file is called mystyle.css and you have a link to the style file in your web site like this:

<link rel="stylesheet" type="text/css" href="~/mystyle.css">

To force the browser to load the file again, you need to change link and the standard practice is to use a parameter in the url (usually a version number). like this:

<link rel="stylesheet" type="text/css" href="~/mystyle.css?version=1.00">

Your style file is going to ignore that version parameter but the browser will notice a change in the link and will load the new style file. Basically, the browser stores the link to the file and if you change the version number, since the link does not match with what your browser has in its cache, it will force the browser to load the file again.