Dynamically defining Undefined variables

I want to replace Undefined variables coming from a form

[dolphinsdock]

I'm trying to pass variables from a form from one page to the next. On the recieving page, I am using the following script to convert the form field values into js variables.

function getParams() {
var idx = document.URL.indexOf('?');
var params = new Array();
if (idx!= -1) {
var pairs = document.URL.substring(idx+1, document.URL.length).split('&');
for (var i=0; i<pairs.length; i++) {
nameVal = pairs[i].split('=');
params[nameVal[0]] = nameVal[1];
 }
}
return params;
}
params = getParams();

Then I'm using this in the body to display the field values in the appropriate places.

C1 = unescape(params["C1"]); document.write(C1);

The problem I'm having it that empty fields display as "undefined" I'd like for empty fields to equal a string of " ", obviously while not disturbing the fields that already contain a value.

I attempted to add

if (typeof params == "undefined") {params = ' ';}

to the getParams function but it did change anything.

I'm fairly new to javascript so your help is very much appreciated.

[Fotiman]

if (typeof params == "undefined") {params = ' ';}

It's not params that's undefined... it's params["C1"].

if( typeof params["C1"] == "undefined" ) 
{ 
 C1 = ""; 
} 
else 
{ 
 C1 = unescape(params["C1"]); 
} 
document.write(C1); 

[dolphinsdock]

Makes sense, and worked great. Thanks.