var v = 3.14;
var r = Math.round(i*2)*0.5;
// exemple :
for (i=0; i<=100; i+=5) {
f = i / 100;
r = Math.round(f * 2)*0.5;
document.write(f + " = " + r + "</br>");
}
// affiche :
0 = 0
0.05 = 0
0.1 = 0
0.15 = 0
0.2 = 0
0.25 = 0.5
0.3 = 0.5
0.35 = 0.5
0.4 = 0.5
0.45 = 0.5
0.5 = 0.5
0.55 = 0.5
0.6 = 0.5
0.65 = 0.5
0.7 = 0.5
0.75 = 1
0.8 = 1
0.85 = 1
0.9 = 1
0.95 = 1
1 = 1