[Javascript] String -> Number impossible

[Marcelo Wolfgang]

Hi list,

First forgive me for posting code up in the email, there's no online
page that I can show the script.
I'm having a terrible, like 2 hours wasted on this terrible error,
trying to figure this out:
Here's the code:

<pre>
array_prices = new Array();
array_prices[1] = '115'; //these values are coming from a db
array_prices[2] = '95';

function getCheckedValue(radioObj) {
	var radioLength = radioObj.length;
	for(var i = 0; i < radioLength; i++) {
		if(radioObj[i].checked) {
		return radioObj[i].value;
		}
	}
}

function updateTotal(){
	total = 0;
	totalField = document.getElementById('valorOnlyNumber');
	for (i=1; i < array_prices.length; i++){
		total = total+(array_prices[i])*(2);// this value works here, but I
hardcoded it
	}
	rdVal = getCheckedValue(document.frm_calcShipping.valFrete);
	if (rdVal != 0){
		total = total+rdVal;
	}
	totalField.innerHTML = total;
}
</pre>

and these are my radios:

<div id="normal-mgprrjscCapital"><input type="radio" value="6.70"
name="valFrete" />R$ 6,70</div>
<div id="normal-mgprrjscInterior"><input type="radio" value="7.20"
name="valFrete" />R$ 7,20</div>
<div id="sedex-mgprrjscCapital"><input type="radio" value="12.60"
name="valFrete" />R$ 12,60</div>
<div id="sedex-mgprrjscInterior"><input type="radio" value="18.60"
name="valFrete" />R$ 18,60</div>

<div id="valor">R$<span id="valorOnlyNumber"> 210.00</span></div>

+++++++++++++++++++++
The problem is that rdVal is always a string, I've tried

rdVal = parseFloat('getCheckedValue(document.frm_calcShipping.valFrete)')

still a string

I can't figure out what to do please someone advice

TIA
Marcelo