function isValidForm(f)
{
	var height, weight;
	
	if (f.txtage.value=='')
	{
		alert('Please enter your age.');
		return false
	}
	if(f.optsex[0]!=null)
	{
		if (!(f.optsex[0].checked || f.optsex[1].checked))
		{ 
			alert('Please enter your sex');
			return false;
		}
	}
	if(parseInt(f.txtage.value)<18)
	{
		alert('you must be over 18.');
		return false;
	}

	height= getHeight(f);
	weight = getWeight(f);
	if(!isMetric())
	{
		if((height <51)||(height>94))
		{
			alert("Please re-enter height!");
			return false;
		}
		if(weight>352)
		{
			alert("You are advised to consult your GP before starting a weight loss program!");			
			return false;
		}
		if(weight<88)
		{
			alert("Your weight is too low!");
			return false;
		}
	}
	else
	{
		if(f.txtheight1.value=="")
		{
			alert("Please re-enter height!");
			return false;
		}
		if((height<130)||(height>240))
		{
			alert("Please re-enter height!");
			return false;
		}
		if((weight>160000))
		{
			alert("You are advised to consult your GP before starting a weight loss program!");			
			return false;
		}

		if((weight<40000)||(weight>160000))
		{
			alert("Please re-enter weight!");
			return false;
		}

	}
	if (!(f.optgoal[0].checked || f.optgoal[1].checked))
	{
		alert('Please enter your goal!');
		return false;
	}
	
 
	if (!(f.C1[0].checked || f.C1[1].checked || f.C1[2].checked || f.C1[3].checked))
	{
		if (!(f.optgoal[1].checked))
		{
			alert('Please enter your weekly weight loss!');
			return false;
		}
	}
	if(f.chkbreast!=null)
       { 
		if(f.chkbreast.checked)
        	{
              	  alert('You are advised to consult your GP before starting any weight loss and/or exercise programme.');
                	return false;
        	}	
	 }
       if(f.chkpregnant!=null)
       { 
	 
		if(f.chkpregnant.checked)
        	{
              	  alert('You are advised to consult your GP before starting any weight loss and/or exercise programme.');
                	return false;
        	}
        }
        

        if(f.eatingdisorder.checked)
        {
                alert('You are advised to consult your GP before starting any weight loss and/or exercise programme.');
                return false;
        }
	if(f.cmbtarget.selectedIndex<=0)
	{
		alert('Please enter a target weight');
		return false;
	}
	return true;
}
function isMetric()
{
	var obj;

	if ((obj=findObj('ismetric'))!=null)
	{
		if(obj.value=="1")
			return true;
		else
			return false;
	}

	return false;
}


function loadTargetWeight()
{
	var f;
	var minTarget;
	var maxTarget;
    var numItems = 0; 
	var selectednum=-1;
	var weight, percentage;
	f = document.forms["fsignin"]
	listClear(f.cmbtarget) 

	minTarget=parseInt(minWeight(getHeight(f),isMetric()));
	
	maxTarget=parseInt(maxWeight(getHeight(f),isMetric()));
	
	
    addOption = new Option("Select Goal Weight" ,"Select Goal Weight" );
    f.cmbtarget.options[numItems++] = addOption; 
	
	if(minTarget==0||maxTarget==0) return;
	var i,kg,g;
	weight = getWeight(f);

	if(isMetric())
	{
		
		minTarget = minTarget * 1000;
		maxTarget = maxTarget * 1000;
		if((weight - weight/5)>minTarget)
		{
			minTarget = weight - weight/5;
			maxTarget = weight;
		}
		if((weight)<maxTarget)
			maxTarget = weight 

		

		for (i = minTarget; i <= maxTarget; i=i+200){
			percentage = -Math.floor((weight-i) * 100 /weight);
			kg = i/1000;
			addOption = new Option(kg + ' Kg   (' + percentage + '% weight loss)',i );
		    f.cmbtarget.options[numItems++] = addOption; 
			if(i==tweightg)
				selectednum = numItems-1
	  	}
		i--
	}
	else
	{
		minTarget = Convert_kg_lbs(minTarget);
		maxTarget = Convert_kg_lbs(maxTarget);

		if((weight - weight/5)>minTarget)
		{
			minTarget = weight - weight/5;
			maxTarget = weight;
		}
		if((weight)<maxTarget)
			maxTarget = weight 
		minTarget = Math.floor(minTarget)
		maxTarget = Math.floor(maxTarget)
		
		for (i = minTarget; i <= maxTarget; i++){
			percentage = Math.floor((weight - i) * 100 /weight );
			addOption = new Option(Math.floor(i/14) + 'st ' + (i % 14) + 'lbs   (' + percentage + '% weight loss)',i );
		    f.cmbtarget.options[numItems++] = addOption; 

			if(i==tweightlbs)
				selectednum = numItems-1
	  	}
		i--;

	}
	f.min_weight.value=minTarget;
	f.max_weight.value=i;
	if(selectednum==-1) selectednum=0;
	f.cmbtarget.selectedIndex= selectednum;	
	
}
function listClear(cmb)
{
	for (var i = cmb.options.length - 1; i >= 0; i--){
    cmb.options[i] = null;
  	}
	cmb.selectedIndex = -1;

}


function minWeight(height, metric)
{
	/*height should be eith in inchs or cm */
	
	if(metric)
		return parseInt((18.5 * height * height /10000) + 0.99) /*1 added to protect rounding*/
	else
		return parseInt((18.5 * Convert_in_cm(height) * Convert_in_cm(height) /10000 + 0.99))
}
function maxWeight(height, metric)
{
	/*height should be eith in inchs or cm */
	if(metric)
		return parseInt(24.99 * height * height /10000)
	else
		return parseInt(24.99 * Convert_in_cm(height) * Convert_in_cm(height) /10000)
}
function Convert_lbs_kg(lbs)
{
	return parseInt(lbs * 0.4536);
}
function Convert_kg_lbs(kg)
{
	return parseInt(kg / 0.4536);
}

function Convert_in_cm(inchs)
{
	return parseInt(inchs * 2.54);
}
function changeMeasure(resetdata, imperial)
{
	var f;
	f = document.forms["fsignin"];
	
	if (imperial==null)
	{
		
		if(f.ismetric.value=="1")
			imperial=false;
		else
			imperial=true;
	}
	
	nu_changeMeasure(f,imperial);
	
	if(imperial)
	{
		
		//imperial to metric imperial = true
		var h = parseInt(f.txtheight1.value) * 12 + parseInt(f.txtheight2.value);
		var w = parseInt(f.txtweight1.value) * 14 + parseInt(f.txtweight2.value==''?0:f.txtweight2.value);

		var mh1, mh2;
		h = h * 2.54;
		h = h +.5;

		mh1 = h / 100;
		mh2 = h % 100;

		w = w * 0.45359237;
		
		f.txtweight1.value=w;
		f.txtweight2.value="";		
		f.txtheight1.value=parseInt(mh1);
		f.txtheight2.value=parseInt(mh2);
	}
	
	else{
		//metric to imperial imperial = null
		var h = parseInt(f.txtheight1.value) * 100 + parseInt(f.txtheight2.value);
		var w = f.txtweight1.value * 2.204622622 + .5;
		var ih1, ih2, iw1, iw2;
		
		h = (h * 0.393700787);
		ih1 = h / 12;
		ih2 = h % 12;
		iw1 = parseInt(w / 14);
		
		iw2 = w - (14 * iw1);

		f.txtheight1.value=parseInt(ih1);
		f.txtheight2.value=parseInt(ih2);
		f.txtweight1.value=parseInt(iw1);
		f.txtweight2.value=parseInt(iw2);

}
	loadTargetWeight();
	
}

function changeTarget()
{
	var f;
	var height,weight;

	
	f = document.forms["fsignin"]
	if(f.optgoal[1].checked)
	{
		listClear(f.cmbtarget) 
		addOption = new Option("Select Goal Weight" ,"Select Goal Weight" );
		f.cmbtarget.options[0] = addOption;
		weight= getWeight(f);
		if(weight!=0)
		{
			if(isMetric())
			{
				addOption = new Option(f.txtweight1.value + 'kg ',weight);
				f.cmbtarget.options[1] = addOption; 
			}
			else
			{
					addOption = new Option(f.txtweight1.value + 'st ' + f.txtweight2.value + 'lbs',weight);
					f.cmbtarget.options[1] = addOption; 
			}
			f.cmbtarget.selectedIndex=1;
		}
		else
			f.cmbtarget.selectedIndex=0;
		f.C1[0].disabled=true;
		f.C1[1].disabled=true;
		f.C1[2].disabled=true;
		f.C1[3].disabled=true;
	}
	else
	{
		f.C1[0].disabled=false;
		f.C1[1].disabled=false;
		f.C1[2].disabled=false;
		f.C1[3].disabled=false;
		loadTargetWeight()		
	}
}
function getWeight(f)
{
	
	if(isMetric())
	{
		if(f.txtweight1.value=='') return 0
		return (parseInt(f.txtweight1.value) * 1000) 
		
	}
	else
	{

		if(f.txtweight1.value=='') return 0
		return (parseInt(f.txtweight1.value) * 14) + parseInt(f.txtweight2.value==''?0:f.txtweight2.value);
	}
}
function getHeight(f)
{
	if(f.txtheight1.value=='') f.txtheight1.value="0"
	if(f.txtheight2.value=='') f.txtheight2.value="0"
		
	if(isMetric())
	{
		return (parseInt(f.txtheight1.value) * 100) + parseInt(f.txtheight2.value)
	}
	else
	{
		return (parseInt(f.txtheight1.value) * 12) + parseInt(f.txtheight2.value);
	}
}