Alert if class is used more than once?

Question

In the following Fiddle, you can click to select rows in the table. If you click the 'Execute' button, an alert will tell you if the class .row_selected is visible or not. This is all working, now I need to elaborate on the rows selected part. The user can only 'Execute' one row at a time, so if one row is selected - yay. If more than one are selected, an error message asking to select only one row. One row to rule them all. Any ideas?

http://jsfiddle.net/BWCBX/34/

jQuery

$("button").click(function () {
    if ($(".row_selected").is(":visible")) {
        alert('Row(s) are selected.')
    } else {
        alert('No rows are selected.')
    }
});

Answer 1

Add a condition with .length see below,

if ($(".row_selected").length > 1) {  //more than one row selected
    alert('Please select one row');
} else if ($(".row_selected").length) { //one row selected
    alert('Row(s) are selected.')
} else {  // none selected
    alert('No rows are selected.')
}

Seems like the row_selected is applied to the row only on selection so you don't need :visible check.

DEMO: http://jsfiddle.net/7wrJC/