function check(){
    if(document.form1.name.value==""){
        alert("Please enter a valid your name.");
        return false;
    }
    if(document.form1.mail.value==""){
        alert("Please enter a valid Email address.");
        return false;
    }
    if(document.form1.mail.value.indexOf("@")<=0){
        alert("Please enter a valid Email address.");
        return false;
    }
    if(document.form1.company.value==""){
        alert("Please enter a valid company name.");
        return false;
    }
    if(document.form1.phone.value==""){
        alert("Please enter a valid phone number.");
        return false;
    }

    return true;
}