three questions about table manipulation with jQuery

Question

1.how to highlight the row when mouse is on,then de-highlight when mouse is out

2.how to update a specified row with new values?

3.how to get number of rows in table?

EDIT: the one with best answer for q2 will be marked as answer for this post:)

Answer 1

1. http://docs.jquery.com/Events/mouseover

I believe you can use this or .hover.

$('tr').mouseover(function() {

    $(this).addClass('over');

}).mouseout(function() {

    $(this).removeClass('over');

});

And add a over class in your CSS.

2. You don't update a row, you update the table cells inside the row.

$('tr:first td:first').text( 'something' )

3.

alert( $('table tr').length ); // count all descendant table rows

Answer 2

One:

$('#mytable').find('tr').hover(function() {
    $(this).addClass('active');
}, function() {
    $(this).removeClass('active');
});

Along with this CSS:

#mytable tr.active td {
    background-color: #ccc;
}

Two:

You said update a "row" but all you can really update is cells, unless you want to create whole new cells.

$(cell).html('Contents');

Or:

var $cell = $('<td>').html('Contents');
$(row).html($cell);

Or if a table row has 3 cells, to update the first one:

$(row).find('td').eq(0).html('Contents');

Three:

$('#mytable').find('tr').length;

Answer 3

For the first question:

$("#table1 tr").hover(
   function()
   {
    $(this).addClass("highlight");
   },
   function()
   {
    $(this).removeClass("highlight");
   }

For the third question:

var count = $("table1 tr").length