SO - 30233696

HTML

<form name="workshop" onsubmit="return addvalidation()">
 
			<td><input path="name"  name="w" id="updateformatWorkshopName${workshop.id}" class="text" maxlength="75"/></td>			
			<td><input path="addr1" value="${workshop.addr1}" name="t" id="updateformatAddress1${workshop.id}" class="text" maxlength="75"/></td>
			<td><input path="addr2" value="${workshop.addr2}" name="a" id="updateformatAddress2${workshop.id}" class="text" maxlength="75"/></td>
			<td><input path="town" value="${workshop.town}" name="c" id="updateformatTown${workshop.id}" class="txtId" maxlength="75"/></td>
			<td><input path="postcode" value="${workshop.postcode}" name="s" id="updateformatPostcode${workshop.id}" class="txtId" maxlength="5"/></td>
    
    <input type="submit" />
</form>

JavaScript

function addvalidation() {
    var form = document.forms["workshop"];
    var ef = ['w', 't', 'a', 'c', 's'].filter(function (f) {
        return !form[f].value
    })

    if (ef.length) {
        alert("Mandatory fields " + ef.join() + " must be filled out");
        return false;
    }
}