Sort out the small tips2 in front-end development in the computer [update in time]

21) Requests supported by the http1.1 standard (the same domain name) are parallel. The number of downloads in each browser is IE6/7 (2), firefox3, and IE8 (6) opera10/chrome3/safari4 (4)

22) when using floating elements in IE6, note that if the width is not set, this may cause problems.

23) if there is an HTML comment between the parent and child elements (div> P), the Child selector does not work in IE7.

24) IFRAME usage: the IFRAME default style has a border, hide display: None, remove the scroll bar and border can be set to: scrolling = "no" frameborder = "no"

25) in IE6 and 7, the default padding of input whose buttons and types are submit cannot be removed. To remove them, you can add overflow: visible.

26) performance optimization, bigpipe should note that: IE6, 7, 8 can introduce up to 32 CSS files, more than will be directly ignored

27) about reflow: adding the body {overflow-Y: Scroll} on the long page can reduce the reflow, and then modify the content of the element when the element is displayed: none, will not cause reflow, and then display.

28) There is a blank question below the image or the image background height is not correct: Set Font-size: 0

29) vertical center problem of images: Generally, line-height can be set to solve the problem. However, in IE6 and 7, font-size must be set to solve the problem. The ordinal number is 0.873 of the height, font-size: height * 0.873

30) Only the hack statement for IE8 \ 0

31) it is best not to set the height of input. You can set the value of padding.

32) sneak into IFRAME on the page. If the object in IFRAME must use window [IFRAME].ContentWindow to obtain, and other operations are the same as the PAGE method.
33)/* @ cc_on! */What does this mean? In fact, this is a special condition annotation of IE, which is not recognized by other browsers. @ cc_on indicates that the condition annotation is enabled. This is not the meaning in IE. Refer to this articleArticle 
Http://blog.163.com/hjysys1314@126/blog/static/10790320820091010112116834/

34) position: relative is not applicable to tables. to use it in a table, you can set a DIV in the table to set the postion: relative attribute of the div.