Javascript 在javascript中获取文本框的值
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/6069146/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
To get value of textbox in javascript
提问by Microsoft Developer
I dont know why my script is not working. I tried to get value of textbox in javascript but its not giving me a value. Value is shown as null.
我不知道为什么我的脚本不起作用。我试图在 javascript 中获取文本框的值，但它没有给我一个值。值显示为空。
//This is the code for my textbox
<td> <input id="demo3" type="text" size="25" runat="server"/><a href="javascript:NewCal('demo3','ddmmmyyyy',true,24)">
<img src="Resources/cal.gif" width="16" height="16" border="0" alt="Pick a date"></a> </td>
//This is how I trid to access textbox
exDateTime = document.getElementById('pCtrl').value;
but exDateTime is remains null. I tried using other ways too, but nothing seen happening..
但 exDateTime 仍然为空。我也尝试使用其他方式，但没有看到任何事情发生..
采纳答案by Ashwin Krishnamurthy
I don't think you are referring to the proper id.
Try document.getElementById("demo3").value
我不认为您指的是正确的 ID。尝试document.getElementById("demo3").value
Or atleast paste the code where your "pCtrl" form field is.
或者至少将代码粘贴到“pCtrl”表单字段所在的位置。
EDIT :Make sure you set the value for the text box in html or using Javascript for example:
编辑：确保您在 html 或使用 Javascript 中设置文本框的值，例如：
<input type='text' id='demo3' value='3'>
and then use document.getElementById("demo3").valueto get the value, otherwise use javascript to assign the value and obtain the value at a later stage using the same.
然后使用document.getElementById("demo3").value获取值，否则使用javascript分配值并在稍后使用相同的阶段获取值。
I hope this helped you.
我希望这对你有帮助。
回答by mplungjan
I bet this is a .net issue
我敢打赌这是一个 .net 问题
Try this:
尝试这个：
<input id="demo3" type="text" size="25" runat="server"/><a
href="#" onclick="NewCal('<%= demo3.ClientID %>','ddmmmyyyy',true,24);
return false"><img src="Resources/cal.gif" width="16" height="16" border="0"
alt="Pick a date"></a>
exDateTime = document.getElementById('<%= demo3.ClientID %>').value;
