random()                 // number between 0 and 1
random(6)                // number between 0 and 6
random(-2,4)             // number between -2 and 4
random([3,4,5])          // vector between [0,0,0] and [3,4,5]
random([3,4,5],[6,7,8])  // vector between [3,4,5] and [6,7,8]

random([thisComp.width,thisComp.height])

random([0,0],[thisComp.width,thisComp.height])

x = random(thisComp.width);
y = random(thisComp.height);
[x,y]

x = random()*thisComp.width;
y = random()*thisComp.height;
[x,y]

seedRandom(3);
random()

seedRandom(999);
random()

random()                 // number between 0 and 1
random(6)                // number between 0 and 6
random(-2,4)             // number between -2 and 4
random([3,4,5])          // vector between [0,0,0] and [3,4,5]
random([3,4,5],[6,7,8])  // vector between [3,4,5] and [6,7,8]

Random Motion After Effects

JavaScript