JS bit budget specifier

For details, see the blog http://www.w3school.com.cn/js/pro_js_operators_bitwise.asp
and ~~ bitwise operator
var testData=2.1;
var testResult=(typeof testData==="number"&&!isNaN(testData) &&testData!==Infinity)?(testData>0)?Math.floor(testData):Math.ceil(testData):0;