function isValidEmail(str){
        return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
    }
			
	function isEmpty(aTextField){
        return (aTextField.value.length==0 || aTextField.value==null);
    }
    
	function isChoosed(aFormField){
		return aFormField.value!=0;
	}
	
	function isValidPassword(aTextField,bTextField){
		return (aTextField.value==bTextField.value);
	}
	
	function passwdLength(aTextField){
		return aTextField.value.length>4;
	}
	
	function validateRegistrationForm(form){
		if(isEmpty(form.user_name) || isEmpty(form.name) || isEmpty(form.user_email) 
			|| isEmpty(form.user_password)	|| isEmpty(form.teamname)){
				alert("Make sure to write in all textfields");
				return false;
		}
		
		if(!isValidEmail(form.user_email.value)){
			alert("the email you have given isn't a valid email");
			return false;
		}

		
		if(!passwdLength(form.user_password)){
			alert("The password length must be 8");
			return false;
		}
		
		if(!isValidPassword(form.user_password,form.repassword)){
			alert("The password must be the same");
			return false;
		}
		

		return true;
	}