Event Listener Fires Twice

[Claus Mygind]

I am baffled as to why an event listener is firing twice on me.

I have two apps that share the same piece of code. Each app has two search buttons, So a total of 4 search buttons. Each executing the same code with different parameters. Of the 4 buttons only one fails by firing twice on a single click.

Here are the buttons as coded in the two apps:

from App1:
<input 
	type="button"         
	id  ="sbReqClient"         
	value="Change Client"         
	class="InputText"
	tabindex="-1" 
/>
<input 
	type="button"         
	id  ="sbComClient"         
	value="Change Client"         
	class="InputText"
	tabindex="-1" 
/>

from App2:
<input 
	type="button"         
	id  ="sbReqClient"         
	value="Change Client"         
	class="InputText"
	tabindex="-1" 
/>
[B]This button when clicked fires twice[/B]
<input 
	type="button"         
	id  ="[B]sbComClient[/B]"         
	value="Change Client"         
	class="InputText"
	tabindex="-1" 
/>

Each button is assigned an event listener like so. I copied this code from the one app to the other app, so the code is identical.

[B]For button 2 in app 2 this eventlistener fires twice.[/B]
	g.sbComClient = document.getElementById('sbComClient');
	if (g.sbComClient.addEventListener)
	{
		g.sbComClient.addEventListener("mousedown",
										function(evt)
										{
											[B]smallSearch[/B]('Client Id','10','8','CLIENT','ID','ComClient','Yes','startSmallSearch');
										},
									false)
	}

	g.sbReqClient = document.getElementById('sbReqClient');
	if (g.sbReqClient.addEventListener)
	{
		g.sbReqClient.addEventListener("mousedown",
										function(evt)
										{
											smallSearch('Client Id','10','8','CLIENT','ID','ReqClient','Yes','startSmallSearch');
										},
									false)
	}

[B]Here is code from app1 which fires properly so you can see all the code involved[/B]
	g.sbComClient = document.getElementById('sbComClient');
	if (g.sbComClient.addEventListener)
	{
		g.sbComClient.addEventListener("mousedown",
										function(evt)
										{
											smallSearch('Client Id','10','8','CLIENT','ID','ComClient','Yes','startSmallSearch');
										},
									false)
	}

	g.sbReqClient = document.getElementById('sbReqClient');
	if (g.sbReqClient.addEventListener)
	{
		g.sbReqClient.addEventListener("mousedown",
										function(evt)
										{
											smallSearch('Client Id','10','8','CLIENT','ID','ReqClient','Yes','startSmallSearch');
										},
									false)
	}

From this point forward all 4 buttons run the exact same code from linked files.

Where should I be looking for the cause of the problem?
What are some possible explanations for multiple firings? I understand double click and that is not the problem, I have checked that.

[Claus Mygind]

I found the error. The one button firing twice had the event listener defined twice. Too much copying of the code. Well there goes 2 hours of my life that could have been spent better.