title: Jquery validation code for not allowed only blank space in textbox
body: <p>i m looking for code in which for not allowed only blank space... for e.g i have one textbox and i have tried this</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$(document).ready(function()
  {  
     $("#mybutton").live('click',function() 
     {
       var txt_family_name=$("#mytextbox").val();
       if(txt_family_name =="" || txt_family_name ==null)
       {
         alert("null"); 
       }
       else
       {
         alert("not null");
       }
     });
  });</code></pre>
  </div>
  </div>
  </p>
  
  <p>this above code i have tried and its not working. so pls help me on that.. on one of my button i m calling this above code</p>
  
  <p>Example : space....with any text -- output should be not null
          : space space.... any space without any other text -- output should be null</p>