<input id="search" type="text" name="MyName" value="Search term" />

<script>
    //  Add and remove search default value on click
    var nameElement = search; // inputfield-id: #search

    function nameFocus( e ) {
        var element = e.target || window.event.srcElement;
        if (element.value == "Search term") element.value = "";
    }

    function nameBlur( e ) {
        var element = e.target || window.event.srcElement;
        if (element.value == "") element.value = "Search term";
    }

    if ( nameElement.addEventListener ) {
        nameElement.addEventListener("focus", nameFocus, false);
        nameElement.addEventListener("blur", nameBlur, false);
    } else if ( nameElement.attachEvent ) {
        nameElement.attachEvent("onfocus", nameFocus);
        nameElement.attachEvent("onblur", nameBlur);
    }
</script>