<html>
<body>
<h1 id="headerId">I'm Header</h1>
<h1 class="headerClass secondClass thirdClass">I'm Header but with class</h1>
<table id="id1">
<tr>
<td class="d">d</td>
<td class="e">e</td>
</tr>
</table>
<table id="id2">
<tr>
<td class="d">ddddd</td>
<td class="e">eeee</td>
</tr>
</table>
</body>
<script>
a=7;
alert(a);
a='uehfuerh';
alert(a);
alert($('#headerId').html());
$('#headerId').html('New header');
$('.headerClass').html('New header for class');
alert($('#headerId').html());
alert($('table#id2 .e').html());
$('table#id2').append('<tr><td>NEW</td> </tr>');
</script>
</html>