<form name="form1" method="post" action="">
<input type="checkbox" name="checkbox" value="aa"> aa
<input type="checkbox" name="checkbox" value="bb"> bb
<input type="checkbox" name="checkbox" value="cc"> cc
<input type="checkbox" name="checkbox" value="dd"> dd
<input name="tt" type="text" id="tt">
<input type="button" onClick="this.form.tt.value=this.form.checkbox[2].value" value="按钮">
</form>
<input type="checkbox" name="checkbox" value="aa"> aa
<input type="checkbox" name="checkbox" value="bb"> bb
<input type="checkbox" name="checkbox" value="cc"> cc
<input type="checkbox" name="checkbox" value="dd"> dd
<input name="tt" type="text" id="tt">
<input type="button" onClick="this.form.tt.value=this.form.checkbox[2].value" value="按钮">
</form>
<script>
function checkvalue(){
var i
for i=0 to 3
{
if(document.form1.checkbox[i]).value!=""
document.form1.tt.value=document.form1.checkbox[i].value
}
}
</script>