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Viewport either require complicated and unintuitive

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viewport, either require complicated and unintuitive style rules, or simple but widely unsupported rules. Absence of expressions There is currently no ability to specify property values as simple expressions (such as margin-left: 10% – 3em + 4px;). This would be useful in a variety of cases, such as calculating the size of columns subject to a constraint on the sum of all columns. However, a working draft with a calc () value to address this limitation has been published by the CSS WG. Internet Explorer versions 5 to 7 support a proprietary expression() statement, with similar functionality. This proprietary expression() statement is no longer supported from Internet Explorer 8 onwards, except in compatibility modes. This decision was taken for standards compliance, browser performance, and security reasons. Lack of column declaration While possible in current CSS 3 (using the column-count module), layouts with multiple columns can be complex to implement in CSS 2.1. With CSS 2.1, the process is often done using floating elements, which are often rendered differently by different browsers, different computer screen shapes, and different screen ratios set on standard monitors. Cannot explicitly declare new scope independently of position Scoping rules for properties such as z-index look for the closest parent element with a position:absolute or position:relative attribute. This odd coupling has undesired effects. For example, it is impossible to avoid declaring a new scope when one is forced to
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adjust an element's position, preventing one from using the desired scope of a parent element. Pseudo-class dynamic behavior not controllable CSS implements pseudo-classes that allow a degree of user feedback by conditional application of alternate styles. One CSS pseudo-class, ":hover", is dynamic (equivalent of JavaScript "onmouseover") and has potential for abuse (e.g., implementing cursor- proximity popups),[39] but CSS has no ability for a client to disable it (no "disable"-like property) or limit its effects (no "nochange"-like values for each property). Cannot name rules There is no way to name a CSS rule, which would allow (for example) client-side scripts to refer to the rule even if its selector changes. Cannot include styles from a rule into another rule. CSS styles often must be duplicated in several rules to achieve a desired effect, causing additional maintenance and requiring more thorough testing. Cannot target specific text without altering markup. Besides the :first-letter pseudo-element, one cannot target specific ranges of text without needing to utilize place-holder elements. 1 http://jigsaw.w3.org/css-validator/ 2 http://www.w3.org/People 3 http://www.webdevout.net/browser-support-summary? IE6=on&IE7=on&IE8=on&FX2=on&FX3=on&OP9=on&uas=CUSTOM 4 http://snook.ca/archives/html_and_css/css-parent-selectors
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