使用十六进制值和变量在jquery中改变.css渐变

I have set a background gradient in the body of a website I'm building. I also have created a menu the items of which change to distinct colors on hover. What I'd like to do is ask just sections of the background gradient to change to the same color of the menu item that is being hovered over. I have been able to use JQuery to alter the background color using preselected hex values. I wonder if it is possible to define these hex values in combination with a variable that selects the color of the "this", or hovered-over item. And if not, if there is another, perhaps simpler way to solve the problem. I have set a background gradient in the body of