How do i show an alert if no results founded

i have this code: http://ift.tt/2imd9lG For example i tap in a searchbar something like "asdfdsas" there will be no result founded,how do i show an alert when no results founded,and the same with checkboxes,thanks.

-HTML

    <script src="http://ift.tt/1oMJErh"></script>
<pre id=result> </pre>

<input type="text" id="searchFlowerNames" placeholder="Type a flower name..."><span id="searchResult"></span>

<div class="flowers-wrap">


    <h3 style="font-size:14px; font-weight:normal;">Available Flowers</h3>
    <p style="font-size:12px;"><strong>Filter flowers by colour:</strong></p>
    <form>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-colour" value="red" id="red" /> Red</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-colour" value="yellow" id="yellow" /> Yellow</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-colour" value="pink" id="pink" /> Pink</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-colour" value="purple" id="purple" /> Purple</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-colour" value="green" id="green" /> Green</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-colour" value="other" id="other" /> Other</label>
    </form>
    <p style="font-size:12px;"><strong>Filter flowers by size:</strong></p>
    <form>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-size" value="tiny" id="tiny" /> Tiny</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-size" value="small" id="small" /> Small</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-size" value="medium" id="medium" /> Medium</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-size" value="large" id="large" /> Large</label>
        <br>
        <label style="font-size:12px;">
            <input type="checkbox" name="fl-size" value="giant" id="giant" /> Giant</label>
    </form>

</div>

<div class="continents-wrap">

    <h3 style="font-size:14px; font-weight:normal;">Available Continents</h3>

    <div class="continents" style="font-size:12px;">
        <div>Africa
            <input type="checkbox" name="fl-cont" value="africa" id="africa" />
        </div>
        <div>Europe
            <input type="checkbox" name="fl-cont" value="europe" id="europe" />
        </div>
        <div>Asia
            <input type="checkbox" name="fl-cont" value="asia" id="asia" />
        </div>
        <div>North America
            <input type="checkbox" name="fl-cont" value="north-america" id="north-america" />
        </div>
        <div>South America
            <input type="checkbox" name="fl-cont" value="south-america" id="south-america" />
        </div>
        <div>Antarctica
            <input type="checkbox" name="fl-cont" value="antarctica" id="antarctica" />
        </div>
        <div>Australasia
            <input type="checkbox" name="fl-cont" value="australasia" id="australasia" />
        </div>
    </div>

</div>

<div class="flowers">
    <div class="flower" data-id="aloe" data-category="green small medium africa">Aloe</div>
    <div class="flower" data-id="lavendar" data-category="purple green medium africa europe">Lavender</div>
    <div class="flower" data-id="stinging-nettle" data-category="green large africa europe asia">Stinging Nettle</div>
    <div class="flower" data-id="gorse" data-category="green yellow large europe">Gorse</div>
    <div class="flower" data-id="hemp" data-category="green large asia">Hemp</div>
    <div class="flower" data-id="titan-arum" data-category="purple other giant asia">Titan Arum</div>
    <div class="flower" data-id="golden-wattle" data-category="green yellow large australasia">Golden Wattle</div>
    <div class="flower" data-id="purple-prairie-clover" data-category="purple green other medium north-america">Purple Prairie Clover</div>
    <div class="flower" data-id="camellia" data-category="pink other large north-america">Camellia</div>
    <div class="flower" data-id="scarlet-carnation" data-category="red medium north-america">Scarlet Carnation</div>
    <div class="flower" data-id="indian-paintbrush" data-category="red medium north-america">Indian Paintbrush</div>
    <div class="flower" data-id="moss-verbena" data-category="purple other small south-america">Moss Verbena</div>
    <div class="flower" data-id="climbing-dayflower" data-category="blue tiny south-america">Climbing Dayflower</div>
    <div class="flower" data-id="antarctic-pearlwort" data-category="green yellow large antarctica">Antarctic Pearlwort</div>
</div>

-CSS

    body {
  font-family: 'Arial';
  color: #646464;
}

.continents-wrap {
  float: left;
  width: 20%;
  margin: 0 5% 0 0;
  padding: 0;
}

.flowers-wrap {
  float: left;
  width: 20%;
  margin: 0 5% 0 0;
  padding: 0;
  position: relative;
}

.flowers {
  float: left;
  width: 50%;
}

.flowers div {
  float: left;
  width: 90%;
  height: 68px;
  line-height: 68px;
  padding: 0 5%;
  background: #eee;
  margin: 0 0 1px;
  position: relative;
}

---

-JS

var $filterCheckboxes = $('input[type="checkbox"]');

$filterCheckboxes.on('change', function() {

    var selectedFilters = {};

    $filterCheckboxes.filter(':checked').each(function() {

        if (!selectedFilters.hasOwnProperty(this.name)) {
            selectedFilters[this.name] = [];
        }

        selectedFilters[this.name].push(this.value);

    });

    // create a collection containing all of the filterable elements
    var $filteredResults = $('.flower');

    // loop over the selected filter name -> (array) values pairs
    $.each(selectedFilters, function(name, filterValues) {

        // filter each .flower element
        $filteredResults = $filteredResults.filter(function() {

            var matched = false,
                currentFilterValues = $(this).data('category').split(' ');

            // loop over each category value in the current .flower's data-category
            $.each(currentFilterValues, function(_, currentFilterValue) {

                // if the current category exists in the selected filters array
                // set matched to true, and stop looping. as we're ORing in each
                // set of filters, we only need to match once

                if ($.inArray(currentFilterValue, filterValues) != -1) {
                    matched = true;
                    return false;
                }
            });

            // if matched is true the current .flower element is returned
            return matched;

        });
    });

    $('.flower').hide().filter($filteredResults).show();



});


var flowerArray = [];
$(".flower").each(function(){
    flowerArray.push($(this).html().toLowerCase());
});
//console.log(flowerArray);


$("#searchFlowerNames").on("input",function(){
    var searchInput = $(this).val().toLowerCase();
    $("input[name='fl-colour']").attr("checked",false);
    $("input[name='fl-size']").attr("checked",false);
    $("input[name='fl-cont']").attr("checked",false);

    if(searchInput!=""){
        $(".flower").hide(); 
        $(".flower").each(function(){

            // We have a match.
            if($(this).html().toLowerCase().indexOf(searchInput) != -1){
                $(this).show();

                // To check the relevant checkboxes, have to get the category of this match.
                var thisFlowerData = $(this).data("category").toLowerCase().split(" ");
                //console.log(thisFlowerData);

                // Set the flower color checkboxes
                $("input[name='fl-colour']").each(function(){
                    if(thisFlowerData.indexOf($(this).val().toLowerCase()) != -1){
                        $(this).prop("checked",true);
                        //console.log($(this).val());
                    }
                });

                // Set the flower size checkboxes
                $("input[name='fl-size']").each(function(){
                    if(thisFlowerData.indexOf($(this).val().toLowerCase()) != -1){
                        $(this).prop("checked",true);
                        //console.log($(this).val());
                    }
                });

                // Set the flower continent checkboxes
                $("input[name='fl-cont']").each(function(){
                    if(thisFlowerData.indexOf($(this).val().toLowerCase()) != -1){
                        $(this).prop("checked",true);
                        //console.log($(this).val());
                    }
                });
            }
        });
    }else{
        $(".flower").show(); 
    }
});