title: check uncheck All checkboxes and count values using data attributes
body: <p>I want to check all the check oxes and calculate the values consisted in the data attributes:-</p>
  
  <pre><code>&lt;table&gt;
    &lt;thead&gt;
      &lt;tr&gt;
        &lt;th style="text-align: center;"&gt;Pay? &lt;input class="chkSelectAllTimeLogs" type="checkbox" /&gt; &lt;/th&gt;
      &lt;/tr&gt;
    &lt;/thead&gt;
  
    &lt;tbody&gt;
      @for (int i = 0; i &lt; 10; i++)
      {
        &lt;tr&gt;
          &lt;td style="text-align: center;"&gt;
            @Html.CheckBoxFor(model =&gt; Model.timeLogCollection[i].IsCheckedTimeLog, new { @class = "timeLogItem", data_amount = i } )
          &lt;/td&gt;
        &lt;/tr&gt;
      }
    &lt;/tbody&gt;
  &lt;/table&gt;
  
  &lt;div id="divTotalAmount" style="text-align: center; font-size: 30px; font-family: Tahoma; font-weight: bold;"&gt;
    0.00
  &lt;/div&gt;
  </code></pre>
  
  <p>What i want is when i click on the the check box with class "chkSelectAllTimeLogs" then 
  1. All the checkboxes with class "timeLogItem" should be checked
  2. The values in the data-amount should be calculated accordingly i.e. on check and uncheck of click of single or multiple.</p>
  
  <p>Currently i have 2 separate functions working as follows:</p>
  
  <p>to mark the check all i have:</p>
  
  <pre><code>jQuery(".chkSelectAllTimeLogs").click(function () {
    if (jQuery(".chkSelectAllTimeLogs").is(':checked')) {
      jQuery(".timeLogItem").prop("checked", true);
    } else {
      jQuery(".timeLogItem").prop("checked", false);
    }
  });
  </code></pre>
  
  <p>to calculate the total i have:</p>
  
  <pre><code>function ehRunningTotalForTimeLogPaymentEntry() {
    /* This event handler monitors the checkboxes for time log items and updates the running total in a DIV. */
    var total = 0;
    jQuery(".timeLogItem").click(function () {
      var amount = jQuery(this).data("amount");
      if (this.checked)
      { total += amount; }
      else
      { total -= amount; }
      jQuery('#divTotalAmount').html(total).formatCurrency();
    });
  }
  </code></pre>
  
  <p>both the functions are in document ready.
  Please let me know how can i accomplish this?</p>
  
  <p>Regards
  Abhishek</p>