the first thing to do is choose a good web browser. My choice is Chrome, because it has a strong debugging tools. When I on Chrome debugging finished, I'll then debugging on Safari or Firefox.
code is as follows:


the return result + 4;

of course, sometimes using hacks in IE6 and IE7 is necessary. For Internet explorer 8, usually only used in compatible with CSS3 need hacks. Under normal circumstances, need to use the hack in IE6/7:
code is as follows:


foo {
background - color: # CCC;/* older browsers will use this */
background - color: rgba (0,0,0,0.2);/* browsers that understand rgba will use this */
}

2. Use the prefix for specific browser
code is as follows:


foo {
background: # 1 e5799;/* Old browsers */
background: -- moz -- linear gradient (top, # 1 e5799 0%, # 2989 50% d8, cca # 207 51%, # 7 db9e8 100%); FF3.6 + *//*
background: webkit - gradient (linear, left, top, left, bottom, color - stop (0%, # 1 e5799), color - stop (50%, # 2989 d8), color - stop (51%, # 207 cca), color - stop (100%, # 7 db9e8));/* Chrome, safari 4 + */
background: -- webkit -- linear gradient (top, # 1 e5799 0%, # 2989 50% d8, cca # 207 51%, # 7 db9e8 100%);/* Chrome10 +, Safari5.1 + */
background: -o - linear gradient (top, # 1 e5799 0%, # 2989 50% d8, cca # 207 51%, # 7 db9e8 100%); Opera 11.10 +/* */
background: - ms - linear - gradient (top, # 1 e5799 0%, # 2989 50% d8, cca # 207 51%, # 7 db9e8 100%);/* ie 10 + */
background: linear - gradient (top, # 1 e5799 0%, # 2989 50% d8, cca # 207 51%, # 7 db9e8 100%); W3C/* */
}

note that this code has two different version of webkit syntax. Prefix code written order should also be starting on older browsers (see article).
if there is a W3C standard defined syntax, you should put it in the last (for example, the code above the last line). Such as the browser to support these new features of standard grammar, your code can also be robust performance.
code is as follows:


clearfix {
overflow: hidden;/* new formatting context in better browsers */
* overflow: visible;/* protect IE7 and older from the overflow property */
* zoom: 1;/* difference hasLayout, IE a new formatting context equivalent */
}

all IE hacks for a version and all of its previous browser, such as:
code is as follows:


foo {
filter: progid: DXImageTransform. Microsoft. The gradient (startColorstr='# 1 e5799, endColorstr=' # 7 db9e8, GradientType=0); 6-9 *//*
}
 

6. Not to the latest version of Firefox, Chrome, Safari use any hacks# 0 - #


This concludes the body part