名字:
<script language = "javascript">
function sizeChange(x){
var len = 3;
if (document.x.value.length > 3 && document.x.value != "")
{len = document.x.value.length
alert(len)}
else {alert(len)}
}
</script>
function sizeChange(x){
var len = 3;
if (document.x.value.length > 3 && document.x.value != "")
{len = document.x.value.length
alert(len)}
else {alert(len)}
}
First Name: <input type="text" name="firstNa" size = "sizeChange("firstNa")">
如何使此代码根据用户输入更改文本框的大小,并使其默认大小为3?该函数似乎没有被调用,并且当我插入测试警告时它返回一个空值。
答案 0 :(得分:1)
您需要使用“ oninput”:
var renderNewSize = function(){
var el = document.getElementById('firstName');
el.size = el.value.length;
}
First Name: <input type="text" name="firstNa" size="3" oninput="renderNewSize()" id="firstName">
答案 1 :(得分:0)
您可以这样做
function change_size(){
let input = document.getElementById("firstNa").value;
document.getElementById("firstNa").size = input.length;
}
First Name: <input type="text" id="firstNa" size = "3" oninput="change_size()">