Form Control JavaScript DHTML

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  3. Form Control
  4. Check form input value and alert user by change the control background


Form Validation

function checkValid() {
    var valueField = document.forms[0]["myValue"];
    if (valueField.value != "A") {
        valueField.style.background = "#FF0000";
        var inputDiv = document.getElementById("inputDiv");
        var feedbackdiv = document.createElement("div");
        feedbackdiv.setAttribute("id","feedback");
        inputDiv.appendChild(feedbackdiv);
        feedbackdiv.appendChild(document.createTextNode("Incorrect myValue."));
        return false;
    } else {
        return true;
    }
}




myValue: 




    function init() {
        document.forms[0].onsubmit = function() { 
           return checkValid() 
        };
    }
    window.onload = init;