function checkInput(theForm) {
	var email_reg_exp = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-]{2,})+\.)+([a-zA-Z0-9]{2,})+$/;

	if ((theForm.yname.value==0) && (theForm.yname.value.length<=0)) {
		alert("Your name is missing !");
		theForm.yname.focus();
		return false
	}

	if ((theForm.company.value==0) && (theForm.company.value.length<=0)) {
		alert("Company name is missing !");
		theForm.company.focus();
		return false
	}

	if ((theForm.telephone.value==0) && (theForm.telephone.value.length<=0)) {
		alert("Your telephone number is missing !");
		theForm.telephone.focus();
		return false
	}

	if ((theForm.email.value==0) && (theForm.email.value.length<=0)) {
		alert("Your e-mail is missing !");
		theForm.email.focus();
		return false
	}

	else if (!email_reg_exp.test(theForm.email.value)){
		alert("E-mail is not valid !");
		theForm.email.focus();
		return false
		}

}