<form name="f">
<input type="text" name="a">
<input type="button" name="b" value="赋值" onClick="document.f.a.value=’搞定了’">
</form>
<form name="f">
<input type="text" name="a">
<input type="button" name="b" value="赋值" onClick="document.f.a.value=’搞定了’">
</form>