Get dynamic id when keyup trigerring using jquery/javascript

Get dynamic id when keyup trigerring using jquery/javascript

I have dynamically showing product list with price and quantity in text
box, i want to calculate product total price when enter the quantity.I
have done this by onclick when increase or decrease button.but i also need
to calculate the total price when key up quantity textbox
My code is like
<div id="gw_articles">
<div id="article_list">
<p>
<div id="article_1_element">
<input type="text" id="jform_article_1_name"
name="jform[article_1][name] " value="Spark plug ARH-II
AIW16 IRIDIUM+" disabled="disabled" size="35" /> <a
id="jform_article_1_modal">Select an product</a>
<input type="hidden" id="jform_article_1_id"
name="jform[article_1][id]" value="2" />
<input type="hidden" name="jform[article_1][price]"
id="jform_article_1_price" value="30.00" class="inputbox"
/>
<input type="text" name="jform[article_1][price_total]"
id="jform_article_1_price_total" value="90"
class="inputbox" size="10" />
<input type="text" name="jform[article_1][quantity]"
id="jform_article_1_quantity" value="3" class="inputbox"
size="10" />
<input type="button" class="btn" value="+"
onclick="document.id('jform_article_1_quantity').value++;
calculateTotalPrice('jform_article_1')" />
<input type="button" class="btn" value="-"
onclick="if(document.id('jform_article_1_quantity').value
>1)document.id('jform_article_1_quantity').value--;
calculateTotalPrice('jform_article_1')" /> <a title="test"
class="btn btn-danger"
onclick="removeElement('article_1_element')"> Delete </a>
</div>
</p>
<p>
<div id="article_2_element">
<input type="text" id="jform_article_2_name"
name="jform[article_2][name] " value="Spark plug ARH-II
AIW20 IRIDIUM+" disabled="disabled" size="35" /> <a
id="jform_article_2_modal" class="btn modal" title="Select
an product">Select an product</a>
<input type="hidden" id="jform_article_2_id"
name="jform[article_2][id]" value="1" />
<input type="hidden" name="jform[article_2][price]"
id="jform_article_2_price" value="40.00" class="inputbox"
/>
<input type="text" name="jform[article_2][price_total]"
id="jform_article_2_price_total" value="40"
class="inputbox" size="10" />
<input type="text" name="jform[article_2][quantity]"
id="jform_article_2_quantity" value="1" class="inputbox"
size="10" />
<input type="button" class="btn" value="+"
onclick="document.id('jform_article_2_quantity').value++;
calculateTotalPrice('jform_article_2')" />
<input type="button" class="btn" value="-"
onclick="if(document.id('jform_article_2_quantity').value
>1)document.id('jform_article_2_quantity').value--;
calculateTotalPrice('jform_article_2')" /> <a title="test"
class="btn btn-danger"
onclick="removeElement('article_2_element')"> Delete </a>
</div>
</p>
</div>
<input type="hidden" id="articles_max" name="articles_max" value="2" />
</div>