根据MIN和MAX数组值更改DIV颜色背景？

In brief explanation, I am retrieving values from an array by using an AJAX call. Green to Red colors background will be displayed depending on the number "aht_value". The colors are being displayed correctly because I manually putted the values in the calculation below. That being said, in my "function conv(x)" I want the values to be dynamic.In brief explanation, I am retrieving values fr