如何在表单上添加其他参数，使用GET方法提交

I have this form :

我有这样的形式：

<form method='GET' name='search' action='index.php?explore=search'> 
    <input type="hidden" name="searchType" value="all" />
    <input class="inputSearchSmall" name="search">
</form>
<a href="/go.html?url=javascript:document.search.submit()"><img src="img/button_search.png" class="buttonSearch" /></a>
<form method='G