有时候⽹页中使⽤箭头以增强效果，⼀般的做法是使⽤图⽚，今天我们使⽤CSSCSS来实现“箭头效果”，使⽤CSS我们必须兼容所有浏览器（IE6、7、8、9、10、+），Chrome，Firefox，Opear...
29 30 31 34 | 35 36 .arrow{ border-width:50px; border-color:red green blue black; border-style:solid solid solid solid} 37 | 38
39 40 41 44 | 45 46 .arrow-top{ border-width:50px; border-color:red transparent transparent transparent; border-style:solid dashed dashed dashed; border-bottom:none;}47 48 | 49
50 51 52 55 | 56 57 .arrow-right{ border-width:50px; border-color:transparent green transparent transparent; border-style:dashed solid dashed dashed; border-left:none;}58 59 | 60
61 62 63 66 | 67 68 .arrow-bottom{ border-width:50px; border-color:transparent transparent blue transparent; border-style:dashed dashed solid dashed; border-top:none;} 69 70 | 71
72 73 74 77 | 78 79 .arrow-left{ border-width:50px; border-color:transparent transparent transparent black; border-style:dashed dashed dashed solid; border-right:none;}80 81 | 82
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