Edit in JSFiddle

function myViewModel() {
    var self = this;
    self.clickHandler = function () {
        alert('click...');
    };
    self.bgColor = ko.observable("gray");

    self.myMouseover = function () {
        self.bgColor("blue");
    };

    self.myMouseout = function () {
        self.bgColor("gray");
    };

    self.data = ko.observable("foo");
    self.isChecked = ko.observable(false);
    self.ddlData = ko.observableArray([
        {t:'a', v:1},
        {t:'b', v:2},
        {t:'c', v:3},
    ]);
};

ko.applyBindings(new myViewModel());

<div data-bind="event: { mouseover: myMouseover, mouseout: myMouseout }, style: { border: 'solid 1px black', backgroundColor: bgColor }">
    <input type="button" value="clickMe" data-bind="click:clickHandler" /><br />
    <input type="checkbox" data-bind="checked:isChecked" />
    <input type="text" data-bind="value:data, enable:isChecked, hasfocus:isChecked" /><br />
    <select data-bind="options:ddlData, optionsText:'t', optionsValue:'v'"></select><br />
</div>