<!DOCTYPEhtml><htmllang="en"><head><metacharset="UTF-8"><title></title><styletype="text/less">/*less的运算操作我们可以在数值及颜色值上做一些基本的运算操作，注意，操作符左右最好是空格。如下*/@span-width:100px;@color:#099999;span{height:50px;display:inline-block;}#left{width:@span-width;background-color:@color;}#right{width:@span-width*2;background-color:@color-100;}</style></head><body><spanid="left">hello1</span><spanid="right">hello2</span><scripttype="text/javascript"src="js/es5-shim.js"></script><scripttype="text/javascript"src="js/less.min.js"></script><scripttype="text/javascript">less.watch();</script></body></html>