How would I make the previous dates in the calendar disable using the following html code?
<div class="form-group">
<label for="rank" class="cols-sm-2 control-label">Date</label>
<div class="cols-sm-10">
<div class="input-group">
<span class="input-group-addon"><i class="fa fa-calendar" aria-hidden="true"></i></span>
<input type="date" id="txtDate" required="Required" class="form-control" name="txtDate" placeholder="Select suitable date" />
</div>
</div>
</div>