How to populate and use an array in Javascript?

**softwareguy74** · Aug 9th, 2004, 11:30 AM

I need to create an array in Javascript in my web page that contains 3 columns:

CategoryID
ReasonID
Value

So for example, I need an array to have the following info:

1,1,Value1
1,2,Value2
1,3,Value3
2,1,Value1
2,2,Value2
2,3,Value3

I will then have 2 comboboxes on my web page. The first combobox will simply contain a CategoryID value. The second combobox needs to be populated based on which CategoryID is selected in combobox 1. So for example, if CategoryID 2 is selected in combobox 1, I need combobox 2 to populated with all values from the array that contain a 2 as the first element.

An example of how to do this would be greatly appreciated.

**riis** · Aug 9th, 2004, 11:58 AM

I'd use objects for this

Code:

// First declare the object type, can be done with a function
function ObjectName(categoryID, reasonID, value)
{
  this.categoryID = categoryID;
  this.reasonID = reasonID;
  this.value = value;
}

// Then declare the array
var myArray = new Array();

// Make an event handler which fills the combo boxes, place it in the body tag, like: <body onload="init()">
function init()
{
  // Fill the array
  myArray.push(
    new ObjectName(1, 1, "Value1"),
    new ObjectName(1, 2, "Value2"),
    ...
    new ObjectName(2, 3, "Value3"));

  // Loop through the array and fill the combobox
  var myCombo = document.getElementById("comboId")';
  for(var i = 0; i < myArray.length; i++)
  {
    myCombo.add(new Option(myArray[i].categoryID, myArray[i].categoryID, false, false);
  }

  return;

}

I hope you can do the rest from here, like filling the second combo box when the user selects a value from the first. If not just put your questions here.
You might read a bit about event handling in JavaScript. You can put an event on a select box the same way as I did on the body tag. Use the onclick event for this purpose.

**softwareguy74** · Aug 9th, 2004, 04:55 PM

Seems to be erroring out on the following line:

myCombo.add(new Option(myArray[i].categoryID, myArray[i].categoryID, false, false);

Any ideas?

**softwareguy74** · Aug 9th, 2004, 05:18 PM

Nevermind, I see that a parenthesis was missing at the end...

**riis** · Aug 10th, 2004, 02:30 AM

Originally posted by dbassettt74
Nevermind, I see that a parenthesis was missing at the end...

Yup, my mistake, didn't test it

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