Home > Article > Web Front-end > css control input tag_html/css_WEB-ITnose
I found this one when I was shopping and I think it is very good
The following is the CSS style
JsCode
}
. The old one I am currently working on has stuck
...
November 24, 2009 1:31:36 Here is a quote from a CSS optimization article by Guai Fei Quote
The biggest problem with the CSS Expression feature in browsers: it will be executed repeatedly, perhaps hundreds or thousands of times per second, causing serious performance problems.
How to optimize CSS Expression?
At the very least: if we execute the CSS Expression only once on the matching element, performance will improve significantly.
Quote
In the CSS Expression statement body, the CSS that will trigger the Expression Property reset.
JsCode
div { zoom: expression(function(el){el.style.zoom = "1"; alert(el.tagName);}(this
));
div { -singlex: expression(this.singlex ? 0 : (function
(t) { alert(t.tagName) ; t.singlex = 0; } )(this
Regarding Expression, the Yahoo team mentioned these
18, avoid using CSSexpression (Expression)
CSS expressions are a powerful (but dangerous) way to dynamically set CSS properties. Internet Explorer supports CSS expressions starting with version 5. In the following example, you can use CSS expressions to switch the background color every hour:
background-color: expression( (new Date()).getHours()%2 ? "#B8D4FF" : "#F08A00" );
As shown above, JavaScript expression is used in expression. CSS properties are set based on the evaluation of JavaScript expressions. The expression method does not work in other browsers, so it is useful to set it up specifically for Internet Explorer in a cross-browser design.
The problem with expressions is that they are evaluated more often than we think. Not only when the page is displayed and zoomed, but also when the page is scrolled and even when the mouse is moved, it will be recalculated. Add a counter to a CSS expression to track how often the expression is evaluated. You can easily achieve more than 10,000 calculations by simply moving the mouse on the page.
One way to reduce the number of times a CSS expression is evaluated is to use a one-time expression, which assigns the result to a specified style attribute the first time it is run, and uses this attribute to replace the CSS expression. If style properties must change dynamically during page cycles, using event handlers instead of CSS expressions is a viable option. If you must use CSS expressions, be sure to remember that they are evaluated thousands of times and may have an impact on the performance of your page.