var isBMI = false;
  var BMI;
  function BMIChange(txtBox){
		switch(txtBox.name){

			case "Wp":
				obj = document.getElementById('Wk');
				if( isValidNumber(txtBox.value) ){
					obj.value = Math.round( Number(txtBox.value) * 0.45359237 * 100) / 100;
				}
				else{
					obj.value = '';
				}
				break;
			case "Wk":
				obj = document.getElementById('Wp');
				if( isValidNumber(txtBox.value) ){
					obj.value = Math.round( Number(txtBox.value) / 0.45359237 * 100) / 100;
				}
				else{
					obj.value = '';
				}
				break;
			case "Hi":
				obj = document.getElementById('Hc');
				if( isValidNumber(txtBox.value) ){
					obj.value = Math.round( Number(txtBox.value) * 2.54 );
				}
				else{
					obj.value = '';
				}
				break;
			case "Hc":
				obj = document.getElementById('Hi');
				if( isValidNumber(txtBox.value) ){
					obj.value = Math.round( Number(txtBox.value) / 2.54 );
				}
				else{
					obj.value = '';
				}
				break;
		}
  }
  
  function calculateBMI(){
		var ret = true;
		var msg = "";
		
		obj1 = document.getElementById('Wk');
		if(!isValidNumber(obj1.value)){
			ret = false;
			msg += "يرجى إدخال رقم صحيح للوزن.\n";
		}
		
		obj2 = document.getElementById('Hc');
		if(!isValidNumber(obj2.value)){
			ret = false;
			msg += "يرجى إدخال رقم صحيح للطول.\n";
		}
		
		if(!ret){
			alert('يرجى تصحيح الأخطاء التالية:\n---------------------------------------------\n'+msg);
		}
		else{
			
			var BMIF = document.getElementById('BMIForm');
			var BMIR = document.getElementById('BMIResult');
			
			
			
			var w = Number(obj1.value);
			var h = Number(obj2.value) / 100; // in meters
			BMI =  w / (h*h);
			BMI = Math.round(BMI * 10) / 10;
				
			var bmiBar = document.getElementById('BMIArrow');
			bmiBar.style.paddingLeft = ( (BMI>40 ? 40 : BMI) * 2.5) + "px";
			
			var bmiValue = document.getElementById('BMIValue');
			if(bmiValue.innerText != null){
				bmiValue.innerText = "مؤشر كتلة جسمك " + (BMI) + "";
			}
			else if(bmiValue.textContent != null){
				bmiValue.textContent = "مؤشر كتلة جسمك " + (BMI) + "";
			}
			
			/////////////// save data in cookies for register page
			document.cookie = "bmibmi=" + escape( BMI ) + ";path=/";
			//document.cookie = "Hi=" + escape( document.getElementById('Hi').value ) + ";path=/";
			document.cookie = "Hc=" + escape( document.getElementById('Hc').value ) + ";path=/";
			//document.cookie = "Wp=" + escape( document.getElementById('Wp').value ) + ";path=/";
			document.cookie = "Wk=" + escape( document.getElementById('Wk').value ) + ";path=/";
			
			
			if(BMI < 18){
				document.getElementById('msg1').style.display = "";
				document.getElementById('msg2').style.display = "none";
				document.getElementById('msg3').style.display = "none";
				//document.getElementById('btnNext').style.display = "none";
			}
			
			if(BMI >= 18 && BMI <= 25){
				document.getElementById('msg1').style.display = "none";
				document.getElementById('msg2').style.display = "";
				document.getElementById('msg3').style.display = "none";
				//document.getElementById('btnNext').style.display = "none";
			}
			
			if(BMI > 25){
				document.getElementById('msg1').style.display = "none";
				document.getElementById('msg2').style.display = "none";
				document.getElementById('msg3').style.display = "";
				/////////////// show next button
				//document.getElementById('btnNext').style.display = "";
			}
			
			BMIF.style.display = "none";
			BMIR.style.display = "";
			
			isBMI = true;
		}
		
		return false;
  }
  
  function backToBMI(){
		var BMIF = document.getElementById('BMIForm');
		var BMIR = document.getElementById('BMIResult');
		
		BMIF.style.display = "";
		BMIR.style.display = "none";
		
		isBMI = false;
		
		return false;
  }
  
  function goToStep2(){
	if(!isBMI){
		alert("You have to check your BMI before\nyou register.");
		return false;
	}
	else{
		document.getElementById('bmibmi').value = BMI;
		return true;
	}
	
  }