Webbrowser How can I create dynamically generated items

My English is not very good, please basic English for answers.

İ want to make a basic C # program to post some forms. This is an example.

This is the source code for the page:

<form>
  <input type='text' id='username' name='username'>
  <input type='password' id='password' name='password'>
  <input type='submit' id='login_button' value='login'>
</form>

      

        
        
        
      

    

My program automatically fills in these inputs and clicks the submit button, each one is ok.

But sometimes clicking the login button form creates a dynamic captcha in the div. I am unable to get the div attributes on the web browser. This is the source code of the page: Example with a dynamically created Div:

<form>
  <input type='text' id='username' name='username'>   
  <input type='password' id='password' name='password'>

      

        
        
        
      

    

/ Dynamic created start Div /

<div class="captcha-item" id="recaptcha_image" style="width: 300px; height: 57px;">
<img style="display:block;" alt="reCAPTCHA sorusu resmi" height="57" width="300" src="http://www.google.com/recaptcha/api/image?c=03AHJ_VusAFaZS5rvfB19q2Emz-7XuayLW3r5OcGO7zzwFrSWoDeaDNRBo1B7lGVTfInKsVP3RBhg_P7_pRhMIajud1GosuIseTrg8C-z8mh2CY_BOiDIj4subsjD3kWP7wk6evBTHxzfOn7ryQrv4aChE9dMy0krKNxl9QbGvMcd43Ig83F22OBViLTITiL9GgpHBNF4M6B0Ja7bg0EGLHxCc-AQIWhtd1A_Mm_A3bgdPg_DzVbTDS3qIRcxbYqJSj3lKHcOYuPSIeCDPfE6773Q8O2utZTx1SA"></div>

      

        
        
        
      

    

/ Dynamic Created Div End /

<input type='submit' id='login_button' value='login'>
</form>

      

        
        
        
      

    

how can i get dynamically generated attributes of an element using c # webbrowser?