Simple pure Javascript drag controller slider

Hi Developers all over the world.

I would like to have some help with a simple, pure Javascript (30 lines), JQuery free (and other library's) drag control slider.

I have been searching months and found many scripts but i don't like -Jquery cause most script need 4, 5, 6 javascript includes.. I prefer smaller and basic script.. i like to ajust them like i want and i also can lean alot from smaller scripts.

All i need is a simple slider that i can use for: rescale images, scroll page, change brightness on images (with PHP) etc.

I am new with javascript (2 months), this is how far i get now.. Sorry for the bad variable names...

---

    <script type="text/javascript">  
      _item = null;
      mouse_x = 0;
      drag_x = 0; 
      function move_init() {
        document.onmousemove = _move;
        document.onmouseup = _stop;
      }
      function _stop(){
         _item = null;
      }
      function _move(e){
        mouse_x = document.all ? window.event.clientX : e.pageX;
        if(_item != null){
             _item.style.left = (mouse_x - drag_x) + "px";
        }
      }
      function _move_item(drag)
      {
        _item = drag;
        drag_x = mouse_x - _item.offsetLeft;
      }
move_init();
drag.onmousedown=_move_item();   // Agh.. did'nt figure out how this works
</script>

<style type="text/css">
#drag{background:#797979;color:#fff;width:30px;height:15px;position:relative;}
#track{background:red; width:200px;}
</style>

<div id="track"><div id="drag" onmousedown="_move_item(this);" >x</div></div>

i appriciate your help.

I wrote this on 31 december 2012.. So happy new year. Please be good for each other.

Thank you.

This code works in modern browsers. Just create some polyfill for that addEventListener and this custom range slider will be safe to use:

function rangeSlider(id, onDrag) {

    var range = document.getElementById(id),
        dragger = range.children[0],
        draggerWidth = 10, // width of your dragger
        down = false,
        rangeWidth, rangeLeft;

    dragger.style.width = draggerWidth + 'px';
    dragger.style.left = -draggerWidth + 'px';
    dragger.style.marginLeft = (draggerWidth / 2) + 'px';

    range.addEventListener("mousedown", function(e) {
        rangeWidth = this.offsetWidth;
        rangeLeft = this.offsetLeft;
        down = true;
        updateDragger(e);
        return false;
    });

    document.addEventListener("mousemove", function(e) {
        updateDragger(e);
    });

    document.addEventListener("mouseup", function() {
        down = false;
    });

    function updateDragger(e) {
        if (down && e.pageX >= rangeLeft && e.pageX <= (rangeLeft + rangeWidth)) {
            dragger.style.left = e.pageX - rangeLeft - draggerWidth + 'px';
            if (typeof onDrag == "function") onDrag(Math.round(((e.pageX - rangeLeft) / rangeWidth) * 100));
        }
    }

}

Example Usage

<style>
.range-slider {
  width:300px;
  height:20px;
  margin:0 auto 1em;
  position:relative;
  cursor:e-resize;
}
.range-slider:before {
  content:"";
  display:block;
  position:absolute;
  top:9px;
  left:0;
  width:100%;
  height:2px;
  background-color:black;
}
.range-slider span {
  display:block;
  height:inherit;
  position:relative;
  z-index:2;
  background-color:red;
  cursor:inherit;
}
</style>

<div class="range-slider" id="range-slider-1">
  <span></span>
</div>

<script>
rangeSlider('range-slider-1', function(value) {
    document.getElementById('test-area').innerHTML = value + '%';
});
</script>

Demo: http://jsbin.com/dulifezi/2/edit

---

Update

I’m creating a repo for this snippet here → https://github.com/taufik-nurrohman/range-slider