Cursor Chaser: Tutorial: The Gurus Network
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atan( dy/dx ) 
// Cursor's in Quadrant II with respect to chaser object. 
else if( dx<0 && dy>=0 ) angle = Math.atan( dy/dx ) + Math.PI 
// Cursor's in Quadrant III with respect to chaser object. 
else if( dx<0 && dy<0 ) angle = Math.atan( dy/dx ) + Math.PI 
// Cursor's in Quadrant IV with respect to chaser object. 
else if( dx>0 && dy<0 ) angle = Math.atan( dy/dx ) + 2*Math.PI 
} else { 
// Cursor is sitting right on the positive y-axis. 
if( dy>0 ) angle = Math.PI/2 
// Cursor is sitting right on the negative y-axis. 
else angle = 1.5*Math.PI 

Compute the fractional move toward the cursor along the x-axis and the y-axis. 
xstep
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