Check form input value and alert user by change the control background : Form Validation « Form Control « JavaScript DHTML






  1. JavaScript DHTML
  2. Form Control
  3. Form Validation

Check form input value and alert user by change the control background

 


<html>
<head>
<title>Form Validation</title>
<script type="text/javascript">
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;
    }
}

</script>
</head>
<body>
<form name="formexample" id="formexample" action="#">
<div id="inputDiv">myValue: <input id="myValue" name="myValue"></div>
<div><input id="submit" type="submit"></div>
</form>
<script type="text/javascript">
    function init() {
        document.forms[0].onsubmit = function() { 
           return checkValid() 
        };
    }
    window.onload = init;
</script>
</body>
</html>








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