Drag object between two points with mouse

I have a slider where I want to move the handle between two points with the mouse/touch.

The handle is rotated to always face the points so if I could move it in x (localposition) towards the closest point to the mouse and clamp it to not travel outside the two points I would be a happy camper.

Anyone got any ideas how to achieve this, this is what I got so far since I can't figure out how to move it in a good way.

Code (csharp):

1.  
2.         Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
3.         mousePos = new Vector3(mousePos.x,mousePos.y,0f);
4.  
5.         target.rotation = Quaternion.LookRotation(Vector3.forward, sliderLeft.position - sliderRight.position);
6.         target.Rotate(0f, 0f, -90f);
7.         target.position = Vector3.MoveTowards(target.position, mousePos, Time.deltaTime * 5f);
8.  

 

Exactly like this.. I can't read flash though Anyone with magic code skills?
http://wonderfl.net/c/c8Yi

 

I actually managed to translate the flash script and get it working. So here it is if anyone wants to do something similar sometime.

Code (csharp):

1.  
2. public transform target; //The draggable buttons transform
3. public transform sliderLeft; //The sliders left endpoint
4. public transform sliderRight; //The sliders right endpoint
5.  
6.     public void UpdateSlider() {
7.         float vX = 0f;
8.         float vY = 0f;
9.         float dX = 0f;
10.         float dY = 0f;
11.         float iX = 0f;
12.         float iY = 0f;
13.         float dotV = 0f;
14.         float t = 0f;
15.  
16.         Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
17.  
18.         vX = sliderRight.position.x - sliderLeft.position.x;
19.         vY = sliderRight.position.y - sliderLeft.position.y;
20.  
21.         dX = mousePos.x - sliderLeft.position.x;
22.         dY = mousePos.y - sliderLeft.position.y;
23.  
24.         dotV = vX * dX + vY * dY;
25.         t = dotV / (vX * vX + vY * vY);
26.         t = Mathf.Clamp(t, 0f, 1f);
27.  
28.         iX = sliderLeft.position.x + vX * t;
29.         iY = sliderLeft.position.y + vY * t;
30.    
31.         target.position = Vector3.MoveTowards(target.position, new Vector3(iX, iY, 0f), Time.deltaTime * 5f);
32.     }
33.  
34.  

 

I've been looking for this for days and there was not a single person solving this! Thanks a lot!