button onclick call javascript function not working

Question

Im trying to call a function when user clicks on the navbar search button but it does not seem to call the javascript fuction and just loads the same page. I have looked at examples and other questions but I dont see anyhing wrong.. Any help would be much appreciated, Here is my code, It is in my Masterpage.aspx:

           <div class='navbar-form navbar-left' role='search'>
                    <div class='inputgroup'>
                         <input class='form-control' id='navinput' type='text' placeholder='Search'/>
                         <button class='btn btn-default' type='submit' id='navsearchbtn' runat='server' onclick='NavToSearch();'>
                             <span class='glyphicon glyphicon-search'></span>
                        </button>
                    </div>       
                </div>

Here is my Js code (also in Masterpage.aspx): I just have the test redirect to see if it works. (The code that i want to implement is in comments please check that is okay as well, I then want to use the input text to search database)

  <script type='text/javascript'>                   
             function NavToSearch() {
                 window.location.href = 'Search.aspx';

                        /*var navsearchText = $('$navinput').text();

                    if (navsearchText == '')
                    {
                        $('$navinput').attr('placeholder', 'Enter Search Text');
                        return false;
                    }
                    else window.location.href = 'Search.aspx'; */
             }
 </script>

UPDATED script/function:

 <script type='text/javascript'>
 function NavToSearch()
                 {                     
                 var navsearchText = $('#navinput').text();

                 if (navsearchText == '')
                 {
                     $('#navinput').attr('placeholder', 'Enter Search Text');
                     return false;
                 }
                 else {
                     window.location.href = 'Search.aspx';
                     //return false;
                 }

                     /*OR
                         $(document).ready(function(){
                             var url = "OrderHistory.aspx";
                             $(location).attr('href',url);
                         })*/                            
             }
        </script>

Answer 1

If youwant just to call the NavToSearch() when the button clicked you have to change the type of the button from submit to button :

<button class='btn btn-default' type='button' id='navsearchbtn' runat='server' onclick='NavToSearch();'>
      <span class='glyphicon glyphicon-search'></span>
</button>

In your commented code you have to replace $ sign by # for the id navinput and also .text() by .val() :

$('#navinput').val();

Instead of :

$('$navinput').text();

Hope this helps.