function checkField(id){
        var Element = document.getElementById(id).value;
        var ElementStar = document.getElementById("star" + id);
        if (Element.length < 5) ElementStar.style.display = "inline";
        else ElementStar.style.display = "none";
        
        checkAllStar();
    }

    function checkEmail(id) {
	    var thisElement = document.getElementById(id);
		var thisElementStar = document.getElementById('star' + id);
		var sEmail = thisElement.value;
		var oRegExp = /^[A-Za-z0-9][-\w]*(\.[A-Za-z0-9][-\w]*)*@[A-Za-z0-9][-\w]*(\.[A-Za-z0-9][-\w]*)*\.[a-zA-Z]{2,4}$/
		sEmail = sEmail.replace( new RegExp('/\(.*?\)/'), '' )
		thisElementStar.style.display = oRegExp.test(sEmail) ? 'none' : 'inline';
		checkAllStar();
	}
    
    function checkAllStar(){
        var ElementSubmit = document.getElementById('submit');  
	    var Container = document.getElementsByTagName('div');
		var isUncomplete = false;
		for (var i = 0; i < Container.length; i++){
		    if ( Container[i].id.substr(0, 4) == 'star' && Container[i].style.display != 'none') isUncomplete = true;
		}
		ElementSubmit.disabled = isUncomplete;
    }