jQuery CSS

I am new to jQuery, my following code not working, there is an error in $ line, can anybody help me:

<script>
function call()
{
    $("div").css("margin-left":200px;);
}
</script>

            <style type="text/css">
                div{margin-left:100px;}
            </style>

<body>
        <div onMouseOver="call();">
                <p>Hallo</p>
        </div>
</body>