function validateForm(){
var form=document.getElementById('liquorreport');
var nameField = form.getElementsByName('declarename')[0];
return nameField.value.match(/\S/) ? true : false;
if(!nameField.value.match(/\S/)){
alert('You forgot to fill out your name!!!');
 return false;
}
}

<form id="liquorreport" action="liquorreport.php" method="post" onsubmit="return validateForm()">