I'm trying to make a battle simulator where you can select classes to fight each other. I can't for the life of me understand what i'm doing wrong!

Code:
<!DOCTYPE html>
<html>
    <head>
        <title>Register</title>
        <!--[if IE]>
            <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script>
        <![endif]-->
        <link href="CSS/styles.css" type="text/css" rel="stylesheet" />

    <script type="text/javascript">
    	
var monsters = {


  reaper : { hitpoints: 250, strength : 17, luck : 3 },


  dragon : { hitpoints: 1000, strength: 50, luck : 5},
  
  orc : { hitpoints: 100, strength: 12, luck : 2 },
  
  ogre: { hitpoints: 50, strength: 10, luck: 1 }
  


}


	
	
	function startFight()
    {
        charFightHP = charHP;
        beastFightHP = beastHP;
        fightTrue = 1;
        charDmg = charStr - beastDef;
        beastDmg = beastStr - charDef;
        beastName = document.getElementById("theBName").innerHTML;

        if (charDmg < 0)
        {
            charDmg = 0;
        }
        else if (beastDmg < 0)
        {
            beastDmg = 0;
        }

        while (fightTrue != 0)
        {
            if (charFightHP > 0 && beastFightHP > 0) 
            {
                charFightHP =  beastDmg - charFightHP;
                beastFightHP = charDmg - beastFightHP;
                alert("You do "+charDmg+" damage to "+beastName+". "+beastName+" does "+beastDmg+" damage to you.");
                document.getElementById("theHP").innerHTML = charFightHP;
                document.getElementById("theBHP").innerHTML = beastFightHP;
            }
            else{
                fightTrue = 0;
            }
        }

        if (beastFightHP < 0 && charFightHP > 0)
        {
            fightWin();
        }

        if (charFightHP < 0)
        {
            alert("You are dead");
            createChar();
        }
    }
	
	
	
	
	
	
	
	
	
	
    </script>

    </head>
    <header>
        
       
        <div style="clear:both;"></div>
    </header>
    <body>
	



        <div id="content">
        		<form class="form">



<h2>Simulator</h2>

<field name="fieldName" static="true" type="FieldType" value="code">Strength</field>


<input type = "text" value="300" disabled="disable" id="hitpoints" />

 <input type = "text" value="100" disabled="disable" id="strength" />
 
 <input type = "text" value="100" disabled="disable" id="luck" />
 
 <select>
  <option>Dragon</option>
  <option>Orc</option>
  <option>Ogre</option>
  <option>Reaper</option>
</select>
 
 
 
 
 
 
 <input type="button" value="Fight" onclick="startFight()";/>
 
	</form>
        </div>
    </body>
    <footer>
    
    </footer>
</html>