Sp-button color styling through JS

I’m trying to change the colors for an sp-button based on the user input. So the button color will change based on one of their other selections. I can get the text color and background color to change. However, the border color doesn’t change. Also, the mouseover doesn’t work to change the mouseover background color.

Am I doing this wrong? Or is it not possible?

document.getElementById("myButtonID").style.backgroundColor="#30bf30"; //works
document.getElementById("myButtonID").style.color="#000000"; //works
document.getElementById("myButtonID").style.borderColor="#30bf30"; //doesn't work
document.getElementById("myButtonID").onmouseover=function(){this.style.backgroundColor="#35d435";} //doesn't work
document.getElementById("myButtonID").onmouseover=function(){document.getElementById("myButtonID").style.backgroundColor="#35d435";} //doesn't work