<button onclick="degistir('x', 0.05)">X Arttır</button>
<button onclick="degistir('x', -0.05)">X Azalt</button>
<button onclick="degistir('y', 0.05)">Y Arttır</button>
<button onclick="degistir('y', -0.05)">Y Azalt</button>

var var1 = 0.95;
var var2 = 0.85;
function degistir(yer, miktar) {
    if(yer == "x")
    {
        var1 = var1+miktar;
    }
    if(yer == "y")
    {
        var2 = var2+miktar;
    }
      document.getElementById("divID").style.transform = "scale("+var1+", "+var2+")";
}