用PHP变量更改元素颜色的Javascript

I am trying to write a Javascript function that changes the font color of an element. I was unsure how to fire off the function right away, so I called the javascript function with an onload call in the element tag. I am retrieving a value through PHP and loading it into the function: if value > 0, set font to green; else if value < 0, set font to red; else, set font to black. Here is what I have so far: I am trying to write a Javascript function that