jQuery - Ability to count the number of Rows in a Table?

w jQuery - is it possible to setup a listener that can count the number of rows in a table.

And when the row count changes d开发者_如何学Co X if the count is eq 0 or Y is > 0?

Thanks

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One way is to use time listener :

 var time = setInterval(function(){   
                                   alert( $('#table tr').length ); 
                                  },1000 ); 

Or you can put it when the event associated with change num rows executed .

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For your first question:

$('table tr').length;

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Both .length and .size() will give you the same information. If the table ID is tbl1, then you use the jQuery CSS selector

$('#tbl1 tr')

If you are using <thead>, <tbody>, <tfoot> properly, then you should use the below to count only the body rows, otherwise take 1 or 2 off the .length result from the above.

$('#tbl1 tbody tr')

As for observing the row count changes, you need either

1. a global var that stores the current row count, coupled with a setInterval event (say 100ms) that checks for changes and raises an event; or
2. a class that encapsulates this behaviour with an internal var, but also using setInterval

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You could use something like:

$('#tableID').bind('DOMNodeInserted', function() {
    var count = $('table tr').length;
    alert("The number of rows has changed, there are now " + count + " rows.");
    });

JS Fiddle demo.