今天看到一段css代码：
[class*=" icon-"]:before,[class^=icon-]:before去stackoverflow上面找了下。
这是原话：
[key^='starts_with'] Will look for elements that have the 'key' attribute whose value starts with 'starts_with'. See CSS3 selectors for more details.
也就是说，[key^='starts_with'] 会查找所有key属性的值以'starts_with'开始的元素。
类似的还有：
[key^='starts_with']
[key$='starts_with']
[key*='starts_with']
举例：
[class^='icon-'] - classes starting with 'icon-' (eg. class='icon-blah blah')
[class$='-icon'] - classes ending with '-icon' (eg. class='blah blah-icon')
[class*='icon'] - classes containing 'icon' (eg. class='blah xxx-icon-blah')
