It is the same question for all programming language/environment (not restricted to EJS).
It always be possible. But the problem is how to let user understand how to use it easily.
Set up a[u] label[/u] on top of a [u]slider[/u] to display " 0.1, 1, 2, 5, 10,50,100",
And add a slider under it for integer value property: for example id (range from 0-6 for the above values).
then add the following code :
case 0: x=0.1; break;
case 1: x=1.0; break;
case 2: x=2.0; break;
May be you can add another text string to display value for x.
You should be able to find different way to do it.