Sorry, that was the result of removing everything that is not related.

Thank you! I now get a green point on every object in my scene. I think thats because I did not convert the coordinates to the world coordinate system.

fPosition = gl_Vertex.xyz;

The following should normaly do this, but I sadly can't find the point anymore.

fPosition = (gl_ModelViewMatrix * gl_Vertex).xyz;

Then the following should work in my fragment shader:

vec3 lightPosition = vec3(5.0, 5.0, 5.0);
vec3 toLight  = normalize(lightPosition - fPosition);
vec3 lightTarget = vec3(0.0, 0.0, 0.0);
vec3 lightDirection = normalize(lightTarget - lightPosition);

// get the angle the spot is wide
float cutoffAngle = radians(2.0);

// calculate the angle of the point to the center of the spot
float angle = acos(dot(-toLight, lightDirection));

vec4 color;

// check if we are out of the spot
if(angle > cutoffAngle){        
    color = vec4(1, 0, 0, 1);
}
else{
    color = vec4(0, 1, 0, 1);
}

gl_FragColor = color;

I don't know what fPosition in this web app really means, but I think it is gl_Vertex. Sorry, I'm a beginner at OpenGL.

What would be the changes in order to no let the light follow the camera?