How to make that at a select'a output it was not reset?

Question

Search Engine Optimization

How to make a search so that when you select the "Width" section and click on the "Find" button, it is not reset, but saved when the result is displayed?)

<form>
   <p>
      <label>Ширина</label>
      <select name="pa_shirina" onchange="selectChanged(this.value);">
      <option value="">—</option>
<option value="6.50">6.50</option><option value="7.00">7.00</option><option value="7.50">7.50</option><option value="8.25">8.25</option><option value="9.00">9.00</option><option value="9.50">9.50</option><option value="10.00">10.00</option><option value="11.00">11.00</option><option value="12.00">12.00</option><option value="13.00">13.00</option><option value="14.00">14.00</option><option value="30">30</option><option value="31">31</option><option value="32">32</option><option value="33">33</option><option value="35">35</option><option value="145">145</option><option value="155">155</option><option value="165">165</option><option value="175">175</option><option value="185">185</option><option value="195">195</option><option value="205">205</option><option value="215">215</option><option value="225">225</option><option value="235">235</option><option value="245">245</option><option value="255">255</option><option value="265">265</option><option value="275">275</option><option value="285">285</option><option value="295">295</option><option value="305">305</option><option value="315">315</option><option value="325">325</option><option value="385">385</option><option value="425">425</option><option value="435">435</option> <option value="445">445</option><option value="500">500</option><em class="wrap-arrow"><em class="arrow"> </em></em>                                
                        </select>
                        </p>
                        <p class="_search">
                                <input class="button" type="submit" value="Мне повезет">
                        </p>
</form>