var brr=[1,2,3,4,5,6,7,8,9]; var start=0; var end=brr.length-1; while(true){ if(start > end){ break; } var mid=parseInt((start+end)/2); if(brr[mid] === 3){ break; }else if(brr[mid] > 3){ end = mid; }else{ start = mid; } }
原文：https://www.cnblogs.com/tanchangsha/p/10203621.html