<script> let testStr = 'helloworld'; let i; let tempObj = {}; for (i = 0; i < testStr.length; i++) { let charAt = testStr.charAt(i); //相当于挨个遍历字符串字符,将字符作为key,出现的次数作为value类似java中的map if (tempObj[charAt]) { tempObj[charAt]++; } else { tempObj[charAt] = 1; } } // console.log(tempObj); //循环遍历对象找到最大数 let max = 0; //初始化一个最大数 let maxStr; let obj; for (obj in tempObj) { if (tempObj[obj] > max) { max = tempObj[obj]; maxStr = obj; } } console.log(maxStr + ':' + max); </script>