デベロッパーツールのconsoleでご確認下さい。
Math.trunc = Math.trunc || function(x) { return x < 0 ? Math.ceil(x) : Math.floor(x); }; console.log(Math.floor(12.34)); // => 12 console.log(Math.floor(56.78)); // => 56 console.log(Math.floor(1.5)); // => 1 console.log(Math.floor(-0.12)); // => -1 console.log(Math.floor(-1.49)); // => -2 console.log(Math.floor(-1.5)); // => -2 console.log('==================='); console.log((12.34).toFixed(0)); // => '12' console.log((56.78).toFixed(0)); // => '57' console.log((1.5).toFixed(0)); // => '2' console.log((-0.12).toFixed(0)); // => '-0' console.log((-1.49).toFixed(0)); // => '-1' console.log((-1.5).toFixed(0)); // => '-2' console.log('==================='); console.log(Math.trunc(12.34)); // => 12 console.log(Math.trunc(56.78)); // => 56 console.log(Math.trunc(1.5)); // => 1 console.log(Math.trunc(-0.12)); // => -0 console.log(Math.trunc(-1.49)); // => -1 console.log(Math.trunc(-1.5)); // => -1