getElementById is null or not an object

[SaipanMan95]

Hi All,

I have been dealing with this terrible little error now for a couple of days. I am sure it is something basic. Here is the situation:

I have set aside 42 Div statements all with a ref Id incrementing from d1 to d42 and reference them via a for loop and inside that loop I pass all the values to a simple function that attempts to write to the div id="d1" and so on. Amazingly it runs fine all the data in appears where it shoul; however, I get this annoying error message saying that document.getElementById(...) is null or not an object.

Here is some sample code:

<!-- The function to reset the date values in the table cells.-->
  // function require currentdate, current day, and number of days in month
  function fillDates(cDate, cDay, noOfDaysInmnth) { 
   	var startDay = (((cDate - (cDay +1))%7)-7);
   	var slotInd, slotName, val, events;  	
  	var j = (startDay)*(-1)+1;
	var m = cmnth + 1;  	
  	//alert(getEvents(7,15));
	for( var i = 1; i <=(noOfDaysInmnth+(j-1)); i++){

		slotName = "d"+j;			
		val = i;
		if( val < 1 || val > noOfDaysInmnth){val = " ";}
		else{val = i;}		
		events = "<br/><i><small>" + getEvents(m,i) + "</small></i>";		
		writeDivs(val, slotName, events);//Writes to Div tags via innerHtml
		j++;
	}//End For Loop	  
  }//fillDates()

<!--"writes the date information to the div blocks" -->
  function writeDivs(d, id, events){
  //d = val; id = slotName; events = events;
	var x, evt, d2, _id;
	if(events == null){ evt = 0;}
	if(events != null){ evt = events;}
		
	if(d == null){ d2 = 0;}
	if(d != null){ d2 = d;}
	
	if(d == 0){ evt = " "; }
            
	x = document.getElementById(id).innerHTML = d2 + evt;//<-this is were the error is occurring
  }//end writit

At first I just ignored this error and posted the code to server but the desired div elements and data wouldn't display. On my own pc it works fine, so I am assumming its this one error message.

here is the table and div structure I use:

<table border=".5" cellpadding="0" cellspacing="" width="100%" style="border-color:#003DAE">

<tr style="border-color:#003DAE"><th>Sun</th><th>Mon</th><th>Tue</th>
	<th>Wed</th><th>Thu</th><th>Fri</th>
	<th>Sat</th></tr>
<tr>
<td><div class="div_1" id="d1">.</div></td>
<td><div class="div_2" id="d2">.</div></td>
<td><div class="div_3" id="d3">.</div></td>
<td><div class="div_4" id="d4">.</div></td>
<td><div class="div_5" id="d5">.</div></td>
<td><div class="div_6" id="d6">.</div></td>
<td><div class="div_7" id="d7">.</div></td>
</tr>
<tr>
<td><div class="div_8" id="d8">.</div></td>
<td><div class="div_9" id="d9">.</div></td>
<td><div class="div_10" id="d10">.</div></td>
<td><div class="div_11" id="d11">.</div></td>
<td><div class="div_12" id="d12">.</div></td>
<td><div class="div_13" id="d13">.</div></td>
<td><div class="div_14" id="d14">.</div></td>
</tr>
<tr>
<td><div class="div_15" id="d15">.</div></td>
<td><div class="div_16" id="d16">.</div></td>
<td><div class="div_17" id="d17">.</div></td>
<td><div class="div_18" id="d18">.</div></td>
<td><div class="div_19" id="d19">.</div></td>
<td><div class="div_20" id="d20">.</div></td>
<td><div class="div_21" id="d21">.</div></td>
</tr>
<tr>
<td><div class="div_22" id="d22">.</div></td>
<td><div class="div_23" id="d23">.</div></td>
<td><div class="div_24" id="d24">.</div></td>
<td><div class="div_25" id="d25">.</div></td>
<td><div class="div_26" id="d26">.</div></td>
<td><div class="div_27" id="d27">.</div></td>
<td><div class="div_28" id="d28">.</div></td>
</tr>
<tr>
<td><div class="div_29" id="d29">.</div></td>
<td><div class="div_30" id="d30">.</div></td>
<td><div class="div_31" id="d31">.</div></td>
<td><div class="div_32" id="d32">.</div></td>
<td><div class="div_33" id="d33">.</div></td>
<td><div class="div_34" id="d34">.</div></td>
<td><div class="div_35" id="d35">.</div></td>
</tr>
<tr>
<td><div class="div_36" id="d36">.</div></td>
<td><div class="div_37" id="d37">.</div></td>
<td><div class="div_38" id="d38">.</div></td>
<td><div class="div_39" id="d39">.</div></td>
<td><div class="div_40" id="d40">.</div></td>
<td><div class="div_41" id="d41">.</div></td>
<td><div class="div_42" id="d42">.</div></td>
</tr>

</table>

any ideas?

[gil davis]

Not sure, but...

for( var i = 1; i <=(noOfDaysInmnth+(j-1)); i++){
...
  j++;

I think the end of the for loop keeps moving.

Put this at the end of the function writeDivs():

if (!document.getElementById(id)) {alert("bad ID = " + id);}

If the value of id > "d42" then you will know that the for loop went too far.

[SaipanMan95]

Thanks....
I tried that alert statement and sure enough the id value was incrementing to 43 and stopping...

I went a head and added...

if(j > 0 && j < 42)
  j++;
else
  break;

after the writeDivs(...) function and no more errors...

Thanks!!!