/*
var contact_text1 = 'Please fill out all three fields in order to submit!';
var contact_text2 = 'Please provide a valid email in order for us to reply you!';
*/
var contact_text1 = '全ての項目にご記入のうえ送信して下さい';
var contact_text2 = '有効なメールアドレスをご記入下さい。';

function submitForm() {
var _1 = document.forms[0].elements[0];
var _2 = document.forms[0].elements[1];
var _3 = document.forms[0].elements[2];
if (_1.value=='' || _2.value=='' || _3.value=='') {
alert(contact_text1);
} else if(!is_valid_email(_2.value)) {
alert(contact_text2);
} else {
document.form.submit();
}
}