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How do I override a base class method in Javascript

Posted on 2008-06-24
7
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Last Modified: 2012-08-14
I have a base class defined as follows
BaseClass = function(id)
{
this.ID = document.getElementById(id);
this.Show() = function() {
document.getElementById(this.ID).style.display = 'block';
};
}
and an inherited class defined as follows

Label = function(id)
{
this.inheritFrom = BaseClass;
this.inheritFrom(id);
}
I want to introduce a Show method on the Label class so that it overrides the base class method, calls the base class method and adds it's own extra implementation for this method.  How can I do this?
Thanks
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Question by:kayhustle
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7 Comments
 
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Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 21863911
use the "super" "object" to call the inherited classes method.
0
 
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Author Comment

by:kayhustle
ID: 21865115
How do I do that?
0
 
LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 21865215
this should explain it all:
http://phrogz.net/JS/Classes/OOPinJS2.html
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Ransomware has become a major concern for organizations; its prevalence has grown due to past successes achieved by threat actors. While each ransomware variant is different, we’ve seen some common tactics and trends used among the authors of the malware.

 
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Author Comment

by:kayhustle
ID: 21867323
Can you give me a code example, not sure I follow your link.
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Author Comment

by:kayhustle
ID: 21867764
Yeah I tried about 4 different variations of what was given in the article and none of them worked.
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LVL 16

Accepted Solution

by:
Lolly-Ink earned 500 total points
ID: 21870721
Here is a working example based on your original code. There were some errors in BaseClass which have been fixed:
<html>

<script>

   BaseClass = function(id)

   {

      this.id = id;

      this.Show = function()

      { 

         document.getElementById(this.id).style.display = 'block';

      }

   }
 

   Label = function(id)

   {

      this.inheritFrom = BaseClass;

      this.inheritFrom(id);

      this._Show = this.Show;

      this.Show = function()

      {

         this._Show();

         document.getElementById(this.id).style.backgroundColor = 'red';

      }

   }
 

   var one = new BaseClass("spanOne");

   var two = new Label("spanTwo");
 

   function load()

   {

      window.setTimeout("changeSpans()", 2000);

   }
 

   function changeSpans()

   {

      one.Show();

      two.Show();

   }

</script>

<body onload="load()">

   <span id="spanOne">One</span>

   <span id="spanTwo">Two</span>

</body>

</html>

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Author Closing Comment

by:kayhustle
ID: 31470352
Perfect!
0

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