title: Regular Expression to Allow Only Numbers
body: <p>i want to give validation condition like,</p>
  
  <pre><code>         var BlkAccountIdV = $('#txtBlkAccountId').val();
       if (BlkAccountIdV == "") {            
          document.getElementById('lblAccountId').innerText = "Enter Valid AccountID";
          errorflag=1;
      } 
  </code></pre>
  
  <p>if condition should be Executed only when entered text box value contains Letter.What value can i give inside Quotation marks(if (BlkAccountIdV == "") )? </p>