页面上有个<input type="hidden" name="num" id="num" value="haha" />我想在页面打开的同时就取到这个input的value
<script type="text/javascript">
var num = document.getElementById("num").value;
alert(num);
</script>报错,弹不出窗口
<script type="text/javascript">
var num = document.getElementById("num").value;
alert(num);
</script>报错,弹不出窗口
<input type="hidden" name="num" id="num" value="haha" />
<script type="text/javascript">
var num = document.getElementById("num").value;
alert(num);
</script>
方式2:<script type="text/javascript">
window.onload =function(){
var num = document.getElementById("num").value;
alert(num);
}
</script>
<input type="hidden" name="num" id="num" value="haha" />
<script type="text/javascript">
//js代码出现顺序无关,在页面html代码全部下载完成后执行
window.onload = function() { alert(document.getElementById('num').value); }
</script>