I have this structure on form,

<input type="test" value="" id="username" />

<span class="input-value">John Smith</span>

<a href="#" class="fill-input">Fill Input</a>

when user click on the Fill Input ,

the data from span which has class input-value will be added to value, after clicking a tag the code should be look like this,

 <input type="test" value="john Smith" id="username" />

    <span class="input-value">John Smith</span>

    <a href="#" class="fill-input">Fill Input</a>

there are many forms element/input on the single page.

thanks!