[html] When to use the !important property in CSS

Consider:

#div p {
    color: red !important;
}
...
#div p {
    color: blue;
}

I understand how !important works. In this case the div will render red because now it has priority (!important). But I can't still figure out an appropriate situation to use it in. Is there an example where !important saves the day?

Overwriting the Style Attribute

Say in the example that you are unable to change the HTML source code but only provide a stylesheet. Some thoughtless person has slapped on a style directly on the element (boo!)

       div { background-color: green !important }

    <div style="background-color:red">_x000D_
    <p>Take that!</p>_x000D_
    </div>

Here, !important can override inline CSS.

Using !important is generally not a good idea in the code itself, but it can be useful in various overrides.

I use Firefox and a dotjs plugin which essentially can run your own custom JS or CSS code on specified websites automatically.

Here's the code for it I use on Twitter that makes the tweet input field always stay on my screen no matter how far I scroll, and for the hyperlinks to always remain the same color.

a, a * {
  color: rgb(34, 136, 85) !important;  
}

.count-inner {
 color: white !important;   
}

.timeline-tweet-box {
 z-index: 99 !important;
position: fixed !important;
left: 5% !important;   
}

Since, thankfully, Twitter developers don't use !important properties much, I can use it to guarantee that the specified styles will be definitely overridden, because without !important they were not overridden sometimes. It really came in handy for me there.

I am planning to use !important for a third-party widget meant to be embedded in a large number of websites out of my control.

I reached the conclusion !important is the only solution to protect the widget's stylesheet from the host stylesheet (apart from iframe and inline styles, which are equally bad). For instance, WordPress uses:

#left-area ul {
    list-style-type: disc;
    padding: 0 0 23px 16px;
    line-height: 26px;
}

This rule threathens to override any UL in my widget because id's have strong specificity. In that case, systematic use of !important seems to be one of the few solutions.

Strictly speaking you shouldn't need to use !important if you've structured your CSS well and don't have too many degrees of specificity.

The most appropriate time to use !important is when you have one exceptional style that you want to style outside of your site's normal cascade.

You use !important to override a css property.

For example, you have a control in ASP.NET and it renders a control with a background blue (in the HTML). You want to change it, and you don't have the source control so you attach a new CSS file and write the same selector and change the color and after it add !important.

Best practices is when you are branding / redesigning SharePoint sites, you use it a lot to override the default styles.

This is a real, real life scenario, because it actually happened yesterday:

• Z-index in jQuery dialog. Autosuggest list not displayed properly

Alternatives to not using !important in my answer included:

• Hunting down in JavaScript/CSS where a certain elusive property was being applied.
• Adding the property with JavaScript, which is little better than using !important.

So, a benefit of !important is that it sometimes saves time. If you use it very sparingly like this, it can be a useful tool.

If you're using it just because you don't understand how specificity works, you're doing it wrong.

Another use for !important is when you're writing some kind of external widget type thing, and you want to be sure that your styles will be the ones applied, see:

• Appended control's CSS

You generally use !important when you've run out of other ways to increase the specificity of a CSS selector.

So once another CSS rule has already dabbled with Ids, inheritance paths and class names, when you need to override that rule then you need to use 'important'.

I'm using !important to change the style of an element on a SharePoint web part. The JavaScript code that builds the elements on the web part is buried many levels deep in the SharePoint inner-workings.

Attempting to find where the style is applied, and then attempting to modify it seems like a lot of wasted effort to me. Using the !important tag in a custom CSS file is much, much easier.

This is a real-world example.

While working with GWT-Bootstrap V2, it will inject some CSS file, which will override my CSS styles. In order to make my properties to be not overridden, I used !important.

!important is somewhat like eval. It isn't a good solution to any problem, and there are very few problems that can't be solved without it.

I have to use !important when I need to overwrite the style of an HTML generated by some JavaScript "plugin" (like advertising, banners, and stuff) that uses the "style" attribute.

So I guess that you can use it when you don't control the CSS.

The use of !important is very import in email creation when inline CSS is the correct answer. It is used in conjunction with @media to change the layout when viewing on different platforms. For instance the way the page looks on desktop as compare to smart phones (ie. change the link placement and size. have the whole page fit within a 480px width as apposed to 640px width.