Cell Color depneding on value of Cell

How do I change the color of a Cell dependant on it's value.

E.g. 0 it's red, over 5 it's blue.

I'm trying this:

grid.defineCellProperty("color", function(row, col){
    if (col = 7){
        if (this.getCellValue(7, row) == 0)
        {
            strColour = "RED";
        }else if (this.getCellValue(7, row)>5)
        {
            strColour = "BLUE";
        }else
    } else {
        strColour = "WHITE";
    }
    return strColour
    })

    grid.getCellTemplate(6).setStyle("background-color", function( ){
        return this.getCellProperty("color");
    });

ignore me - i was getting the col wrong, it should have been column 7 :)

Literally found that 5 mins after posting, been looking on and off for 2 days!