script.aculo.us Sliders onChange Option

Last Updated : 30 Dec, 2020

The script.aculo.us library is a cross-browser library that aims at improving the user interface of a website. The Slider controls are thin tracks that allow the user to input values. It is done by defining a range of values that can be selected by the user by dragging the handle to the appropriate value.

The onChange option is used to specify a callback function that would be invoked whenever the value of the slider changes, either when the slider has finished moving or using the setValue() method to set a new value. The current value of the slider would be passed as a parameter to the function.

Syntax:

{ onChange: function }

Parameters: This option has a single value as mentioned above and described below:

function: This is a callback function that would be invoked whenever the slider has finished moving or has been changed using the setValue() method.

The below example illustrates the use of this option.

Example:

HTML

<!DOCTYPE html> 
<html> 
<head> 
  <!-- Include the required scripts -->
  <script type="text/javascript" 
          src="prototype.js"> 
  </script> 
  <script type="text/javascript"
          src="scriptaculous.js?load = slider"> 
  </script> 
  
  <!-- Style the Sliders so that they 
  are properly visible -->
  <style type="text/css"> 
    .track { 
      width: 250px; 
      background-color: orange; 
      height: 5px; 
      position: relative; 
    } 
  
    .track .handle { 
      width: 20px; 
      height: 10px; 
      background-color: green; 
      cursor: move; 
      position: absolute; 
      top: -2px; 
    } 
  
    .pad { 
      padding: 25px 15px; 
    } 
  </style> 
</head> 
<body> 
    
<p> 
  <h1 style="color: green;"> 
    GeeksforGeeks 
  </h1> 
  <h2>Sliders onChange Option</h2> 
    
<p> 
    The onChange callback function  
    gets invoked whenever the value 
    changes. The value of the slider  
    can be set using the setValue method. 
  </p> 
  
  
  <div class="pad"> 
    <div id="track-hor" class="track"> 
      <div id="handle-hor" class="handle"> 
      </div> 
    </div> 
  </div> 
  
  <input type="text" id="val"> 
  <button onclick="setVal()"> 
    Set Value 
  </button> 
  
    
<p>Current Slider Value:  
    <span id="out">0</span> 
  </p> 
  
  
  <script type="text/javascript"> 
  
    // Initialize the slider 
    let slider = new Control.Slider('handle-hor', 
      'track-hor', { 
        
      // Define the range 
      range: $R(1, 100), 
  
      onChange: function (currValue) { 
        document.querySelector("#out") 
                  .textContent = currValue; 
      } 
    }); 
  
    function setVal() { 
  
      // Get the value form the input box 
      let val = 
          document.querySelector("#val") 
                    .value; 
  
      // Set the value of the slider 
      // to the given value 
      slider.setValue(val); 
    } 
  </script> 
</body> 
</html>