function echeck(str) {

        var at="@"
        var dot="."
        var lat=str.indexOf(at)
        var lstr=str.length
        var ldot=str.indexOf(dot)
        if (str.indexOf(at)==-1){
           alert("Please enter valid email")
           return false
        }

        if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
           alert("Please enter valid email")
           return false
        }

        if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
            alert("Please enter valid email")
            return false
        }

         if (str.indexOf(at,(lat+1))!=-1){
            alert("Please enter valid email")
            return false
         }

         if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
            alert("Please enter valid email")
            return false
         }

         if (str.indexOf(dot,(lat+2))==-1){
            alert("Please enter valid email")
            return false
         }
       
         if (str.indexOf(" ")!=-1){
            alert("Please enter valid email")
            return false
         }

          return true                   
    }
   
function check_form(form) {
    var name=form.name;
    if (name.value == '') {
        alert('Please enter your name');
        name.focus();
        return false;
    }
   
    var email=form.email;
    if (email.value == '') {alert('Please enter your email'); email.focus(); return false;}
    if (!echeck(email.value)) {email.focus(); return false;}
    var phone=form.phone;
    if (phone.value == '') {
        alert('Please enter your phone number');
        name.focus();
        return false;
    }
    return true;
}