Need help implementing a javascript function

[justapimp]

I have a device control panel that consist of a veiw and settings buttons. the buttons are binded to a dataset that populates the devicenumber and deviceUID
I have a javascrip function

function gotoGeo(name, duid)
{
        var username = document.getElementById('txtUsername');
	top.main.location.href="../TrackApp/main.aspx?selectedTab=1&deviceName=" + name + "&deviceUID=" + duid + "&username=" + username;
}

the txtUsername texbox is define after the above script and my buttons are programed to access this function like this:

onclick='javascript:gotoGeo("<%# DataBinder.Eval(Container.DataItems "Name")%>", <%# DataBinder.Eval(Container.DataItems "UID")%>)'

because the device name can consist of blank spaces I surrounded that parameter between a double quotes.

On the code behind, I have another set of data that I am binding to. and that information cannot be binded to the button controls. So, I binded the data to an invisible textfield and Now i would like to use it as an input parameter to either the control or the javafunction

Can anyone help?

I try to use the method bellow but does not work.

I first create a variable name named
var name;

and assign the value of the textbox to the name variable

name = document.getElementById('txtUsername').value;

I then used that variable as the first parameter
in the onclick button behavior.

<input type="button" value="View" onclick='javascript:gotoGeo('name', "<%# DataBinder.Eval(Container.DataItems "Name")%>", <%# DataBinder.Eval(Container.DataItems "UID")%>);'>

since I am new to this web development and javascripting stuff, I don't know if the implementation is correct. the key question is how do I implement this so username has the value of the textbox? Every changes that I made return an undefined value.

[justapimp]

I solved the problem and think you for your suggestions. I couldn't have done without your input. What I did, was I allow the function to have two input parameters which will be supplied by the onclick event of the buttons.

I declared the variable username inside the gotoGeo method and I then call the document.getElementById() and assign it the txtUsername object (and it works).