javascript - Pre fill form subject without php from other page -

i'm having problem contact form. need/want prefill contact form's subject based on price table index.html page.

so have index.htm , contact.html. have contact form on contact.html , pricing table in index.html. need, when click on table#1 directed contact form , prefill subject table#1.

i have button/link in price table pointing to:

<a href="contactos.html#contact-form" class="grey white-text waves-effect waves-light btn-large">escolher</a> 

and in contact form subject field is:

<input id="textarea1" type="text" name="_subject" class="validate"></textarea>     <label for="textarea1">assunto</label> 

my server doesn't have php, can use javascrip/jquery if needed. how can pass subject value contact form index.html button.