[javascript] Can I use jQuery to check whether at least one checkbox is checked?

I have the following HTML form which can have many checkboxes. When the submit button is clicked, I want the user to get a javascript alert to check at least one checkbox if none are checked. Is there an easy way to do this using jQuery?

<form name = "frmTest" id="frmTest">
  <input type="checkbox" value="true" checked="true" name="chk[120]">
  <input type="checkbox" value="true" checked="true" name="chk[128]">
  <input type="checkbox" name="chk[130]">
  <input type="checkbox" name="chk[143]">
  <input type="submit" name="btnsubmit" value="Submit">
</form>

$("#show").click(function() {
    var count_checked = $("[name='chk[]']:checked").length; // count the checked rows
        if(count_checked == 0) 
        {
            alert("Please select any record to delete.");
            return false;
        }
        if(count_checked == 1) {
            alert("Record Selected:"+count_checked);

        } else {
            alert("Record Selected:"+count_checked);
          }
});

$('#frmTest input:checked').length > 0

$("#frmTest").submit(function(){
    var checked = $("#frmText input:checked").length > 0;
    if (!checked){
        alert("Please check at least one checkbox");
        return false;
    }
});

$('#frmTest').submit(function(){
    if(!$('#frmTest input[type="checkbox"]').is(':checked')){
      alert("Please check at least one.");
      return false;
    }
});

is(':checked') will return true if at least one or more of the checkboxes are checked.

if(jQuery('#frmTest input[type=checkbox]:checked').length) { … }