// JavaScript Document

// validates that the field value string has one or more characters in it
function isNotEmpty(elem) {
	var str = elem.value;
    var field = elem.id;
    var re = /.+/;
    if(!str.match(re)) {
        alert("Please fill in " + field + ".");
        return false;
    } else {
        return true;
    }
}
//validates that the entry is a positive or negative number
function isNumber(elem) {
	var str = elem.value;
    var re = /^[-]?\d*\.?\d*$/;
    str = str.toString();
    if (!str.match(re)) {
        alert("This is not a valid number.");
		elem.value = "";
        return false;
    }
    return true;
}

// validates that the entry is formatted as an e-mail address
function isEMailAddr(elem) {
	var str = elem.value;
    var re = /^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/;
    if (!str.match(re)) {
        alert("This is not a valid emailaddress.");
        return false;
    } else {
        return true;
    }
}

// block submission form enter key
function blockEnter(evt) {
    evt = (evt) ? evt : event;
    var charCode = (evt.charCode) ? evt.charCode :
        ((evt.which) ? evt.which : evt.keyCode);
    if (charCode == 13) {
        return false;
    } else {
        return true;
    }
}