window.onLoad question

**ccoder** · Aug 21st, 2001, 04:36 PM

When the onLoad event occurs, do all of the forms objects exist? I think that references to objects in the form are causing the code to terminate. Could it be that the objects don't exist at this time? I get no error message and the page displays without some lists being populated.

I am trying to use some javascript code that I found at The JavascriptSource and I think there is a problem with the code that is executed by the window.onLoad statement. But then, I am very new to java & javascript, so I could be missing something.

Here is the code in question. There are 2 alerts in the first for loop that I used for debugging. I'll refer to them later.

Code:

   function getYears()
    {
     // build the year list - we only need to see last year & the current year
     timeC = new Date();
     currYear = timeC.getFullYear() - 1;
     
     for (var i = 0; i < document.frmSelect.year.length; i++) 
         {
          alert("i = " + i);
          document.frmSelect.year.options[0] = null;
          alert("i = " + i);
         }
     for (var i = 0; i < document.frmSelect.year.length; i++) 
         {
          document.frmSelect.selYear.options[i] = new Option(currYear++);
         }
     document.frmSelect.selYear.options[1].selected=true;
    }  // end select_init

   window.onLoad = getYears();

   //  End -->
  </SCRIPT>
 </HEAD>
 <FORM NAME="frmSelect">
  <FONT FACE="arial">
  <CENTER><B><FONT SIZE="+2">Incident Information</FONT></B></CENTER><HR>
  <FONT SIZE="-1">Select from the following to access the desired data.  Then press <b>Display Graph</B>.<BR>
  Device/station:&nbsp
  <SELECT NAME="selLocale">
   <OPTION VALUE="M1">Mumbai - station A
   <OPTION VALUE="M2">Mumbai - station B
  </SELECT><BR>
  Incident Date:&nbsp;&nbsp</FONT>
  <SELECT NAME="selYear" ONCHANGE="populate(this.form,this.form.selMonth.selectedIndex);">
   <OPTION> </OPTION>
   <OPTION> </OPTION>
  </SELECT>&nbsp

Leaving the option text blank, nothing is populated in the year list and I never see an alert. I also get no error, which I find curious.

If I change the first for statement to

Code:

     for (var i = 0; i < 2; i++) 
         {
          alert("i = " + i);
          document.frmSelect.year.options[0] = null;
          alert("i = " + i);
         }

then I see the first alert, but not the second. The reference to document.frmSelect.year.length has been replaced with the hardcoded value 2, making document.frmSelect.year.options[0] the first reference to frmSelect. This is the basis for my belief that the reference to the form/object is terminating code execution.

One other question. What's up with the statement in the above for loop? Why is the subscript set to 0 (zero) and not i? There is another function that updates the day list whenever the onChange event occurs for the year or month. It uses the same algorithm and works, but I have no idea why.

**Psyrus** · Aug 21st, 2001, 07:19 PM

Try commenting this out:

//window.onLoad = getYears();

and add this to the BODY tag:

<body ONLOAD = "getYears();">

See if that makes a difference.

**ccoder** · Aug 22nd, 2001, 08:43 AM

Originally posted by Psyrus
Try commenting this out:

//window.onLoad = getYears();

and add this to the BODY tag:

<body ONLOAD = "getYears();">

See if that makes a difference.

I had already tried that with the same result.

I don't know if it makes a difference, but I'm using frames and this is one of 3 forms on the page.

**ccoder** · Aug 22nd, 2001, 01:34 PM

I got tired of beating myself over the head with this one so I started calling around the company for some guidence. Someone suggested I put script inside the <select> </select> tags and that worked for me.

I got rid of the window.onLoad statement and the getYears function. The rest of the code that I originally posted now looks like this:

Code:

 
</HEAD>
 <FORM NAME="frmSelect">
  <FONT FACE="arial">
  <CENTER><B><FONT SIZE="+2">Incident Information</FONT></B></CENTER><HR>
  <FONT SIZE="-1">Select from the following to access the desired data.  Then press <b>Display Graph</B>.<BR>
  Device/station:&nbsp
  <SELECT NAME="selLocal">
   <OPTION VALUE="M1">Mumbai - station A
   <OPTION VALUE="M2">Mumbai - station B
  </SELECT><BR>
  Incident Date:&nbsp;&nbsp</FONT>
  <SELECT NAME="selYear" ONCHANGE="populate(this.form,this.form.selMonth.selectedIndex);">
   <SCRIPT LANGUAGE="JavaScript">
    // build the year list - we only need to see last year & the current year
    timeC = new Date();
    currYear = timeC.getFullYear() - 1;
    
    for (var i = 0; i < 2; i++) 
        {
         document.frmSelect.selYear.options[i] = new Option(currYear++);
        }
    document.frmSelect.selYear.options[1].selected=true;
   </SCRIPT>
  </SELECT>&nbsp

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