I want to package up a widget to be easily included in an arbitrary project. I don't want to require that the user link to my personally-created style sheet in their host page - I just want the css to be magically injected when they use my code.
I understand that CssResource can go some ways towards this dream, but after scouring documentation I haven't found any reference to natural type selectors. For instance, I want to style the <tr>s in my widget without having to add a class name to each one.
Is this achievable with GWT? GWT's own widgets all come pretty thoroughly styled, but it seems they've added a style class to every single element in the DOM!
You're on the right track - a CssResource or UiBinder's inline <ui:style> will achieve what you're looking for. With regards to styling elements by type instead of class it certainly can be done:
<ui:UiBinder>
<ui:style>
.myTable tr {
color: red;
}
</ui:style>
<table class="{style.myTable}">
<tr><td>A row!</td></tr>
</table>
</ui:UiBinder>
GWT, however, has a reason for preferring explicit class names over descendent selectors: if you have the above style, for example, every time the browser renders a <tr> element it has to walk up the DOM and visit all of the ancestors of that element to see if any of them have the .myTable class. If your application uses a lot of <tr> elements (<div> would be a better example here), most of which don't have a .myTable ancestor, it can cause a noticeable decrease in rendering performance.
I think, I would use UiBinder, and only give the outermost element a class name, like this:
<ui:style>
.outer tr {
...
}
</ui:style>
<div class="{style.outer}">
...
<tr>...</tr>
...
</div>
Now you don't have to assign a class to each tr - you just use the selector ".outer tr", which only applies to <tr>s within some element marked with the class attribute {style.outer} (doesn't have to be a <div> by the way). The same principle would work without UiBinder, too, of course.
Ok I didn't really understand the whole question, maybe still don't but I think your asking for a way to "bulletproof your CSS" from specificity - I get the CSS bit now after seeing the other answers
Unique classnames (a bit of a oxymoron is CSS terms but heyho) added to everything are advised by most to make sure the site (not your) CSS fails as quickly as possible no matter how specific (weighted) their rules are
But you can make you widget CSS completely unique, i.e. so that it cannot be overruled by a site CSS,no matter how many ID's are in their selectors, without very much ado and without specifically classifying everything
e.g. #mywidget div {} could be overruled by site CSS very easily #wrapper #content div {} will do it - your div is a descendant of those two ID's too, and as their rule had 2 ID's versus your one, your CSS will lose - it's impossible to guess every permutation of a site CSS so the easiest thing is to add all those "extra" classes and why YUI and Blueprint are as they are
however if you write your CSS: #mywidget>div {} yours will likely always win, as never in their CSS will a div they're targetting likely be an immediate child of your widget ID (unless of course they choose to customise yours, which they could do with the 'class everything' method too)
so to bulletproof your CSS without adding classes to everything .. I assume your widget already has a unique iD wrapper? then if you don't already have an inner div wrapper, add one, it doesn't need to have a class but giving it one will place an extra layer of bulletproofing on this technique.
then prefix all your rules with #mywidget>div.myclass e.g. #mywidget>div.myclass td {} - the sites own rules, no matter how heavily weighted (many ID's and classes in a selector make a selector more weighted) theirs will fail as soon as they cannot match that particular combination - so your tr's are safe from site CSS takeover ;)
add one div or class and search and replace your CSS to add the prefix to everything.. as for how to package I've no idea
Related
I have a css file which styles my tables, although I have one table where I would like to use a different style, or no style? is there a way I can do something like <table style="no-style"> and then it is plain and ignores the CSS?
I have looked but I can not find anything related!
Use class definitions for table properties in your CSS file. Whenever you want them, use with class property.
CSS
table.myClass {
...
}
HTML
<table class="myClass">...</table>
<table class="anotherTableWithAnotherClass">...</table>
CSS are cascading style sheets, they only style an element. Can't manipulate anything. You will need to use JavaScript.
Best way I know of, is to use CSS classes for different styles. And use javascript to switch them or remove them.
You need to explore CSS in more depth, and one thing you might focus on is classes. You can create a "class" of styles, and apply it to a particular HTML element like a table, and not have it affect another table you want to leave "plain."
.foo {
border : 1px solid black;
}
Then apply that class to your HTML element:
<table class="foo">
...
</table>
Another way to approach the problem is with selectors.
No, you cannot take off a style that way – there is no way in CSS to say “don’t apply any of my styles inside this particular element.” You can only override style settings. For example, if you have a setting like * { color: red } in your stylesheet (just a foolish example), you cannot add a rule that would exclude a particular element and make the browser apply its default color inside it. But you can set table#foo * { color: black; } to make all text inside a table with id=foo have the black color.
Overriding overall style settings inside a table that way isn’t trivial, but certainly possible. You just need to be explicit about the style you want; you cannot say “use browser defaults.”
However, there’s an indirect way, in a sense, though it is seldom a good idea: If you put your table in a separate document and embed it via an iframe element, then the table will be displayed according to the CSS code specified for the embedded document, quite independently of the style sheets for the embedding document. At the extreme, if you specify no CSS code for the embedded document, it will appear as per browser defaults (though inside a subwindow, an inline frame, with dimensions set by the embedding document).
I am trying to use one CSS class to many DIV. Is it a good practice? or else are there any disadvantages of doing that. because in VS it says "another object already uses this ID", not an error message but a warning.
CSS classes are meant to be reused. CSS IDs are meant to be used uniquely on a component. Are you sure you're using a css class?
There is nothing wrong with styling multiple divs at the same time. This is actually expected and not many people do that. To style all divs;
body {Body Code Here;}
div {Div styling here;}
Styling all div's with one class;
body {Body Code Here;}
div.YourClass {Div Styling Here;}
Notice how there is no space between the div and selector(.) That specifies a class in any div where as div .YourClass will search in all divs for a class. IDs are different than Classes, you can have multiple Classes on the page but only 1 ID on the page. To fix that message, make sure you are using Class instead of ID and search the page for that ID and if it comes up twice or more, thats your problem. Again Classes are reusable and IDs are single-element selectors. Hope I helped!
In css, class is meant to be reused, so it is ok. In case you don't know about id, id in css is meant to be used noce. But nowadays, I've seen few people use class all over place even they just use it once. So, just keep your markup and styling clear, use class or id in your way if you work alone [ personal project ] and keep it persistence when working alone or in a team.
html
<div class="class1 class2">afd</div>
<div class="button class1">asffsdf</div>
css
.class1 { /* styling your class1 here */ }
It is absolutely fine to use the same class for many elements in CSS. Be careful not to do the same for the "id" attribute, which really should only be used for a single element as it is considered a unique ID.
You can use same CSS class for any number of elements, but ID must be unique for each and every element in the page
ID is somewhat different from class. You can have multiple classes on page but ID should only be used once. Do follow best practices :)
i know... this information is not what exactly you want as answer but may be of some little help :)
example:
div.className { } //covers all div with a particular classname
I always was told to take out multiple properties in your css that you use more then once, and add them all in one rule. Like below. (please excuse the poor example)
I always seen this:
.button, .list, .items { color: #444; }
With multiple rules, can't that leave a lot of clutter?
Only in css tutorials and examples Ive seen this:
.someColor { color: #444; }
And in the css, just add another class of '.sameColor'. (div class="button someColor")
I've never seen this and feels like it would leave less clutter in your CSS. Would this be okay? Or do you think it could leave with more clutter in your HTML ?
Try to name your classes independently of their visual effect. It is a nature of CSS to play with the design and layout without having to change the HTML. Class names such as .someColor or .left-sidebar are a bad practice. Colors and position can change.
And also apply rules to semantic HTML elements rather than adding classes on all different divs and spans. It should be obvious, although many people get this wrong.
CSS is a limited set of rules and that makes it a perfect creativity stimulator.
It's all based on personal preference. I've tried both methods and prefer the second method you listed, except with more generic class names such as middleParagraph or headerGraphic so it applies to an area rather than a specific color because colors can change.
Good classnames and IDs are the first place you should optimize. THEN move onto multiple class names.
Multiple classnames can help out quite a bit though, consider:
<div class="leftColumn">Left</div>
<div class="rightColumn">Right</div>
<div class="middleColumn hasLeft hasRight">I have padding-left of 210px and padding-right of 210px</div>
<!-- alternatively, you could have -->
<div class="rightColumn">Right</div>
<div class="middleColumn hasRignt">I have padding right of 210px</div>
<!-- or -->
<div class="leftColumn">Left</div>
<div class="middleColumn hasLeft">I have padding left of 210px</div>
<!-- or -->
<div class="middleColumn">I have no padding</div>
and your css
.leftColumn { width:200px; float:left; }
.rightColumn { width:200px; float:right; }
.middleColumn.hasLeft { padding-left:210px; }
.middleColumn.hasRight { padding-right:210px; }
The result is floated right/left columns and the center area compensates for them with padding. This means you can style your middleColumn how you want to (e.g. .middleColumn .otherCoolSelector ).
It's perfectly acceptable to apply multiple classes to HTML elements. The trick is to be judicious; I usually find that when I do this, the additional classes are additions or exceptions to the basic styling being applied. For example, here are some classes I occasionally add to an element that already has a class:
error -- to style the current element if the user entered invalid data
first -- to style the first element in a list or in a table row, e.g. to suppress padding-left
last -- to style the final element in a list or in a table row, e.g. to suppress margin-right
even -- to apply zebra-striping to alternate elements
hidden -- to hide an element if it's not currently relevant
These extra classes are typically generated dynamically with a server-side language like ASP.NET or PHP. They can also be added or removed on the client side with JavaScript, esp. with a library like jQuery. This is especially useful to show or hide elements in response to an event.
There are a lot of good answers here. The trick is finding out which one fits your situation best.
One thing to consider is your markup size. In a high-traffic situation, your markup size is critical to the speed of your page loads...every byte counts. If this is the case for you, then you may want to create more CSS classes and put less in your markup. That way, the client is caching more and your website is serving up less.
What you're suggesting is a bit like an in-line style, e.g. style="color:#444". So if you want to change the color of your element you'd have to make a change to the html, which means you've defined style as part of your content. Which is exactly what css is supposed to avoid.
Imagine if you'd included 'someColor,' multiple times across multiple html files and you decide some of these elements shouldn't have 'someColor,' after all, you've got a lot of files to go through.
I'd probably avoid the list option too, if I'm making a component, say a button, I want to find .mybutton class in my css file and see all the rules for that component, without having to go through all sorts of unhelpful global classes. Also if someone comes along and changes the color in our global class he may break my button, where as if the button controlled it's own styles it can't be broken in this way.
I have a page that looks like: <div id="header">...</div><div id="navigation">...</div> similar for body and footer.
I'd like to use a grid system to style the page, all of which seem to rely on giving the divs mentioned a class based on their presentation. But I don't want to do this (and can't because of the way the markup is generated)
Is there a way to do this, without just putting a class on the divs? I could copy the details of the class desired to a stylesheet mentioning the divs by id, but that feels wrong.
Edit to clarify:
The OP wants to avoid adding class="grid_3" etc. to the HTML, but also doesn't want to add #header { width: 960px; margin: 0px; } (which I think is okay) – Rory Fitzpatrick 3 hours ago
Exactly, I don't want to put presentation information in my HTML, but I hoped I wouldn't have to just take the css classes that make up the grid system apart, and apply the relevant parts (like margin:0px and width:960px), since that is bad from a maintenance and reuse angle.
So, I'll look at an automated system for doing what I need, unless there is an answer to how do you apply a css class to an HTML element, using css, without adding class="blah" to that element? Because that doesn't seem like a crazy thing to want to do to me.
Well if you use blueprint-css as your grid system you can use the compress.rb to assign the rules for given bp framework classes to a specific selector of your choice like #footer or what have you. for example in your project yaml you could have:
semantic_styles: # i dont think this is the right key definition but you get the idea
'#footer,#navigation': ['span-12','clearfix']
'#footer': ['push-1']
# etc...
Then when you call compress.rb on the project file it will roll up the necessary declaration from the array of selectors on the right into the selector on the left producing:
#footer,#navigation{ /* composite delcalrations from .span-12 and .clearfix */}
#footer {/* declarations from .push-1 */}
But all in all this is essential an automation of copying the declarations to a separate file that you say seems "wrong". But i mean other than doing this (automated or manually) i dont see what the possible options could be.
I'm not sure I understand the question. Why don't you want to put styles in a stylesheet and reference them by id?
#header{
position:relative;
...
}
I have the same reservations about grid systems, adding class names just goes against separating markup and style (but is often sacrificed for productivity).
However, I don't see what's wrong with setting the right column widths and margins using your own CSS. You could have a specific site.grid.css file that contains only selectors and widths/margins for the grid. I think this is perfectly okay, it's just a way of using CSS like variables. For instance, all 3-column elements would appear under
/* 3-column elements, width 301px */
#sidebar, #foobar, #content .aside {
width: 301px;
}
Then rather than adding class="grid_3" to your HTML, you just add the selector to the CSS.
You might want to consider using the class names initially, until you're happy with the layout, then convert it into CSS selectors. Whichever works best for your workflow.
If you don't have access to the markup you must either copy the styles, referencing the ids, or maybe you can apply the class to the ids using javascript?
I am finding it useful to define 'marker' css styles such as 'hidden' or 'selected' so I can easily mark something as hidden or selected - especially when using a tag based technology like ASP.NET MVC or PHP.
.hidden
{
display:none;
}
.newsItemList li.selected
{
background-color: yellow;
}
I don't especially feel like reinventing the wheel here and wanted to know what other things like this are useful or common - or if there are any pitfalls to watch out for.
Should I look at any specific css frameworks for other things like this? Plus is there a name for this type of css class that I can search by.
I agree with the other posters who say only to define what you need, rather than bloating your code with a bunch of unnecessary classes.
That being said, I find myself using the following on a constant basis:
.accessibility - visually hide elements, but keep them intact for screenreaders and print stylesheets
.clear - tied to Easy Clearing
.first-child and .last-child - easily assign styles to the first/last item in a container. This has been a lifesaver many times, and I prefer it over the poorly-supported :pseudo selectors
.replace - tied to Phark IR for transparent image replacement
Finally, I dynamically assign .js to the <html> element with
<script type="text/javascript">if(h=document.documentElement)h.className+=" js"</script>
This will allow me to define .js (rest of selector) styles to target only browsers with JavaScript enabled.
Let me give you an answer from a very novice web developer who has recently considered using CSS classes as "markers". Please don't take this as a definitive answer, as I may be completely wrong, but look at it as another point of view.
I was going to use some marker classes, too. I created one called .center to center the elements in a DIV tag. However, I was struck with the idea that I'm looking at CSS all wrong. I reasoned that CSS is supposed to define how an element is to be displayed without having to change the HTML page. By using marker classes, like .center for example, I would have to change BOTH the CSS and HTML if I wanted that DIV tag to be right-justified next month. So instead, I created a .latestHeader class (the DIV is to hold the "latest information" such as a news item), and in that class I set the text to align center. Now, when I want to change the justification of the text, I simply change the CSS for that DIV and I don't have to touch the HTML.
In regards to your question about CSS frameworks...
Personally I've always found the W3C has the most complex but also most accurate answer to any CSS question.
After many years of programming and playing around with CSS/HTML/PHP I agree with the above comment.
There is no harm in defining a marker for something to be centered or right-aligned using something along the lines of a '.center' or '.righths', but keep in mind as above that if you want to change a whole slab of text your work will be increased because you have to edit both CSS and HTML.
Defining the format for a whole section will mostly likely work out more logical, because if you want to change the section months down the trail, you just have to edit the format of one CSS declaration as opposed to editing each individual article.
CSS was however designed as the ultimate styling language which could allow an administrator to make a website look exactly what they want it to. Keep in mind though that excess CSS will increase the load on a server, will increase the time before your client sees your page and in line with the 'feng shui of web design' it is possible to go overboard with too much styling.
You should really grow this list on a need basis instead of soliciting a list of generic classes across the board--you'll only end up with bloat. If you want to avoid reinventing the wheel the look into some CSS frameworks (blueprint or 960). In some respect, generic classes like .center { text-align:center } do have some level of redundancy but often times they're needed. For example the following pattern which is all too common but should be avoided:
element.onclick(function(e){ this.style.backgroundColor = 'yellow' }
That's bad because you really ought to be using:
element.onclick(function(e){ this.className = 'highlight' }
The latter allows you to modify your styles by only touching the CSS files. But if a CSS class name has only one style element then you should probably avoid it because it doesn't make any sense to have it (.hidden in your example) and call it directly instead:
element.onclick(function(e){ this.display = 'hidden}
I often find myself keeping two classes in all of my stylesheets: "center" (which simply applies text-align: center;, and a float-clearing class that applies clear:both;.
I've considered adding a "reset" statement to all my styles, but haven't had a need for it yet. The reset statement would be something similar to this:
*
{
margin: 0;
padding: 0;
}
I reuse these often enough to include them in just about everything. They're small enough so I don't feel they bloat the code at all.