打印杨辉三角 --JS

var arr = new Array();for(var i = 0 ;i < 6 ; i++){if(i == 0){arr.push(1);}else if(i == 1){arr = new Array();arr.push(1);arr.push(1);}else{var arr2 = new Array();arr2.push(1);for(var j = 0;j<arr.length - 1; j++){arr2.push(arr[j] + arr[j+1]);}arr2.push(1);arr = new Array();arr = arr2;}console.log(arr.join(" "));}