Question

javascript中<input type="text" name="username" value="3">value=3怎样改成等于4

<script language="javascript">
function Test(){
var t1 = document.getElementsByName("username");｝</script>
<form><input type="text" name="username" value="3" >
<input type="button" value="返回值" name="us" onClick="Test()"></form>
怎样将value="3"换成4
谢谢

Answer 1

给input设个ID 然后是GetElementById("intput的ID").value="4";

Answer 2

<script language="javascript">
function Test() {
var t1 = document.getElementsByName("username");
t1[0].value = '4';
}</script>
<form><input type="text" name="username" value="3" >
<input type="button" value="返回值" name="username" onClick="Test()"></form>

追问

function Test(){
var t1 = document.getElementsByName("username");｝

怎样将value="3"换成4
谢谢

追答

function Test() {
var t1 = document.getElementsByName("username");
t1[0].value = '4';
}

Answer 3

<input type="text" name="username" value="3" id="username">
使用jquery
<script language="javascript">
function Test(){
$("#username").val('4');
}
</script>