/**
* [float_add 浮点数加加]
* @param {[type]} _num [description]
* @return {[type]} [description]
*/
function float_add(_num){
var r1, r2, m, arg;
try {
r1 = _num.toString().split(".")[1].length;
} catch (e) {
r1 = 0
}
arg = 1/Math.pow(10,r1);
try {
r2 = arg.toString().split(".")[1].length;
} catch (e) {
r2 = 0
}
m = Math.pow(10, Math.max(r1, r2));
return (_num * m + arg * m) / m;
}
效果如图