First,I find the most frequently occurring element and record this element and its number of occurrences. Then I compare the times with n/2.

```
/**
* @param {number[]} nums
* @return {number}
*/
var majorityElement = function(nums) {
let max = 0, res
for (let i = 0; i < nums.length; i++) {
let count = 0
if (nums[i] != 'a') {
let temp = nums[i]
for (let j = i; j < nums.length; j++) {
if (nums[j] === temp) {
count ++
nums[j] = 'a'
}
}
if (count > max) {
max = count
res = temp
}
}
}
let halfLen = Math.floor(nums.length / 2)
if (max >= halfLen) {
return res
}
return null
};
```