JavaScript - Can't Calculate When Button Click

hey all,
I have had a go at another calculator I am making and got stuck. I want to use the F value determined by the first toggle button in the calculation. I dont understand why the calculation wont work as it is stated in the if/else statement. Any suggestions what i am doing wrong?

here is the code:
Code:

<script type="text/javascript">
    function toggle(btn) {
        var radioSelection = btn.value;

        if (radioSelection == "PO") {
            var F = 0.7;
        }
        else {
            var F = 1;
        }
    }
   
    function toggle(btn) {
        var radioSelection = btn.value;


        var weightInput = document.getElementById("weightRow");
        var CPsInput = document.getElementById("CPsRow");
        var creInput = document.getElementById("creRow");
        var CHFInput = document.getElementById("CHFrow");
        var LDOutput = document.getElementById("LDrow");
        var MDOutput = document.getElementById("MDrow");

        if (radioSelection == "MD") {
            weightInput.style.display = "none";
            CPsInput.style.display = "block";
            creInput.style.display = "block";
            CHFInput.style.display = "block";
            MDOutput.style.display = "block";
            LDOutput.style.display = "none";
        }
        else {
            weightInput.style.display = "block";
            CPsInput.style.display = "none";
            creInput.style.display = "none";
            CHFInput.style.display = "none";
            MDOutput.style.display = "none";
            LDOutput.style.display = "block";

        }

    }


    
    function calculate() {
        var LD = 1;
        var MD = 1;
        var VD = 7.3;
        var CPd = 1.5;
        var Cl = 1;
        var S = 1;
        var T = 1;
        var weight = document.getElementById("weight").value - 0;
        var CHD = document.getElementById("CHD").value;
        var creatinine = document.getElementById("creatinine").value - 0;
        var CPs = document.getElementById("CPs").value -0;



        if (CHD == "Y") {
            Cl = 23 + (0.88 * creatinine);
        LD = (VD * weight * CPd) / (S * F);
        MD = (CPs * Cl * T) / (F * S);
        }

        else {
        Cl = 57 + (1.02 * creatinine);
        LD = (VD * weight * CPd) / (S * F);
        MD = (CPs * Cl * T) / (F * S);
        }


        var LD = Math.floor(LD / 125) * 125
        var MD = Math.floor(MD / 62.5) * 62.5


        document.getElementById('LD').innerHTML = LD + " micrograms - NOTE: if loading dose is above 500micrograms, give in divided doses of no more than 500micrograms at one time";
        document.getElementById('MD').innerHTML = MD + " micrograms";
        document.getElementById('F').innerHTML = F;
        document.getElementById('S').innerHTML = S;

    }
</script>

    <br />
    <br />
    <br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
    <strong>Please select the route to be used for administering digoxin:</strong><br />
<input type="radio" name="route" value="PO" checked onclick="toggle(this);">Oral<br />
<input type="radio" name="route" value="IV" onclick="toggle(this);">Intravenous<br />
<br />
<br />
    <strong>Now select whether you wish to calculate a Loading or Maintenance dose:</strong><br />
<input type="radio" name="dosage" value="LD" checked onclick="toggle(this);">Loading Dose<br />
<input type="radio" name="dosage" value="MD" onclick="toggle(this);">Maintenance Dose<br />
<br />
<br />
<table>
<tr id="CPsRow" style="display:none">
	<td class="style19">Patient's Digoxin Level</td><td class="style17"><input id='CPs' value=""/> micrograms/L </td><td> 
    <ul>
        <li>Ensure that the level has been taken at least 6 hours post dose. Time to steady state is 10-14 days after initiation/dose
change (if renal function is normal).</li>
    </ul>
    </td>
</tr>
<tr id="weightRow" style="display:block">
<td class="style19">Weight</td><td class="style17"><input id='weight' value=""/> kg</td>
</tr>
<tr id="creRow" style="display:none">
<td class="style19">Creatinine</td><td class="style17"><input id='creatinine'/> mmol/L</td>
</tr>
<tr id ="CHFrow" style="display:none">
<td class="style19">Chronic Heart Failure </td><td class="style18"><select id='CHD'> <option value="N">No</option><option value="Y">Yes</option></select></td>
</tr>
</table><br />
<input type="button" onclick="calculate()" value="Calculate!"/><input id="Reset" 
        type="reset" value="Reset" />
<br />
<br />
<br />
<br />

<table>
<tr id="LDrow" style="display:block"><td><strong>Loading dose: </strong> </td><td id='LD' /></td></tr>
<tr id="MDrow" style="display:none"><td><strong>Maintenance dose: </strong> </td><td id='MD' /></td></tr>
<tr><td><strong>Bioavailability factor used: </strong></td><td id='F' /></td></tr>
<tr><td><strong>Salt factor used: </strong> </td><td id='S' /></td></tr>
    </table>

I am having trouble with figuring a way to set my loop up to reset values of the different coin values. Example, when I put in 78, and click calculate, it tells you how much of each coin would be given back. My problem is that I set it up and run it, but when I put different values in back to back to calculate, some of the fields don't reset. I just need some ideas or logic behind what I need to do.

Code:

var change_out = function(){

	
	do {
	var money = document.getElementById("cents").value;
	
	if (money >= 25)
	{
	var quarters = parseInt(money / 25);
	var foo = parseInt(money - (quarters * 25));
	document.getElementById("quarters").value = quarters;
	
		
	
			if (foo >= 10)
			{
			var left = parseInt(foo / 10);
			var wow = parseInt(foo - (left * 10));
			document.getElementById("dimes").value = left;
			if(wow==0)return;
		
			
			
					if (wow >= 5)
					{
					var dumb = parseInt(wow / 5);
					var pop = parseInt(wow - (dumb * 5));
					document.getElementById("nickels").value = dumb;
					document.getElementById("pennies").value = pop;
			
					}else{document.getElementById("pennies").value = wow;}
					
			
			}else if (foo >= 5){
				var dumb = parseInt(foo / 5);
				var pop = parseInt(foo - (dumb * 5));
				document.getElementById("nickels").value = dumb;
				document.getElementById("pennies").value = pop;
				
				}else{document.getElementById("pennies").value = foo;}
			
			
	
	}else if (money >= 10){
		var left = parseInt(money / 10);
		var wow = parseInt(money - (left * 10));
		document.getElementById("dimes").value = left;
		
				if (wow > 5){
				var dumb = parseInt(wow / 5);
				var pop = parseInt(wow - (dumb * 5));
				document.getElementById("nickels").value = dumb;
				document.getElementById("pennies").value = pop;
				document.getElementById("quarters").value = "";
		
				}else{document.getElementById("pennies").value = wow;}
				
	}else if (money >= 5){
		var dumb = parseInt(money / 5);
		var pop = parseInt(money - (dumb * 5));
		document.getElementById("nickels").value = dumb;
		document.getElementById("pennies").value = pop;
		document.getElementById("quarters").value = "";
		document.getElementById("dimes").value = "";
		
	}else{
	document.getElementById("pennies").value = money;
	document.getElementById("quarters").value = "";
	document.getElementById("dimes").value = "";
	document.getElementById("nickels").value = "";
	
	
	
	
	}
	
	
	
	}while(isNaN(money))}

I need this code to calculate the sales tax when you hit the submit button and I can't get it to work. I need to figure out how to connect it to the function. Can someone please point out where I am going wrong? I am very new at this and am woundering what I am doing wrong with my code. This is homework, I am not looking for the answer I just need someone to direct me in the right way.Thanx

Here is my Code: I need this code to calculate the sales tax when you hit the submit button and I can't get it to work. Can someone please point out where I am going wrong?

Code:
<script type="text/javascript">
/*<![CDATA [*/
//Shipping & handling fee



function calculateShipping()
{
var num = new Number(price);
//This will add $1.50 to any purchases that are less than or equal to $25.00.
if (num <= 25){
return 1.5;
//Here 10% will be added to any purchase that is greater than $25.00 but do not inlcude the

$1.50 fee.
} else{
return num * 10 / 100;
}
}
window.alert("Your total is $" + total + ".")

/* ]]> */
</script>
</head>

<body>
<h1>Enter Purchase Price Here</h1>

<script type="text/javascript">
/* <![CDATA[ */

document.write(parseFloat");
if(price <=25.00){var shipping=1.50}
else{var shipping=price*(10/100)};
var total=(price+shipping).toFixed(2);


/* ]]> */
</script>


<form id="btncalcprice" action="submit-form.php">
<input type='text' name='query'>
</form>

<form>
<input type="button" value="Submit" onClick="alert('YOUR total is $'); return true">

</form>
</body>

I would like for the script to say "Ok here is the button on this page *clicks* (or submit)"

I have tried this with out help, I'm not really sure what to do. I've tried learning what I can on my own, I've tried using the search tool.

Here is the part of the code I am trying to use to make my click button.

Code:

<div id="interactiveBox"> 
    <div class="divpad3">
              
                    <form name="buyform" method="POST" action="/marketplace/userstore/2690240/buy/?id=567595175&amp;step=submit" ENCTYPE="application/x-www-form-urlencoded">
                <strong>Buy It Now</strong> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                <strong>Password</strong> <input type="password" class="marketplaceInputField" name="password">
                <input type="hidden" name="nonce" value="860307364.1283901229.441212630">
                <button type="submit" class="cta-button-sm"><span>Buy Now</span></button>
                <br /><br />
            </form>

Here is what I have tried and failed.. This code will be used in combination with greasemonkey

Code:

<script>function clickOnLoad()
{
document.buyform.submit.value = "true";
}

body onload="clickOnLoad()"</script>

Hey

I want to enforce a click on the facebook share button, please help me out here.

I was thinking something like this:
Code:

javascript:window.location="http://www.facebook.com/connect/prompt_feed.php?locale=en_US&message=hi"; javascript:function selectFirst() { publish.focus(); publish.click();}  selectFirst();

Something wrong with that code? What code would work? Is it not possible?

Thanks a lot,
Sarah