如何使用javascript获取按钮ID？ [英] How to get the button id using javascript?

问题描述

 
 Usercontrol有一个id = hdnBtn的按钮，如下所示，
 
  <   pre     lang   =  asp >  
& lt;％@ Control Language =C＃AutoEventWireup =trueCodeBehind =Header.ascx.csInherits =M2iSTS2.UserControl.Header％& gt; 
 
& lt; link href =/ Styles / styles.css =stylesheettype =text / css/& gt; 
& lt; script language =javascripttype =text / javascriptsrc =../ Script / Map.js& gt;& lt; / script& gt; 
 
& lt;！DOCTYPE html PUBLIC -  // W3C // DTD XHTML 1.0 Transitional // ENhttp://www.w3.org/TR/xhtml1/DTD/xhtml1- transitional.dtd&安培; GT; 
 
& lt; input type =buttonvalue =Button1id =hdnBtnrunat =serveronserverclick =assignValue/& gt; 
& lt; div id =headerclass =header& gt; 
& lt; h1 class =h1& gt; TrackU：学生和车辆跟踪系统& lt; / h1& gt; 
& lt; p class =p& gt;& lt; a class =ahref =/ Account / login.aspxönclick='setSession（）'& gt; Logout& ; LT; / A&安培; GT;&安培; LT; / p&安培; GT; 
& lt; / div& gt; 
& lt; div& gt; 
& lt; ul class =ul& gt; 
& lt; li class =li& gt;& lt; a class =liahref =/ Admin / Fleet.aspx& gt; Fleet& lt; / a& gt ;&安培; LT /立安培; GT; 
& lt; li class =li& gt;& lt; a class =liahref =/ Admin / StudentInfo.aspx& gt; Student Info& lt; / a& GT;&安培; LT /立安培; GT; 
& lt; li class =li& gt;& lt; a class =liahref =/ Admin / RouteSettings.aspx& gt;路线设置& lt; / a& GT;&安培; LT /立安培; GT; 
& lt; li class =li& gt;& lt; a class =liahref =/ Admin / Reports.aspx& gt; Reports& lt; / a& gt ;&安培; LT /立安培; GT; 
& lt; / ul& gt; 
& lt; / div& gt; 
 
 
 <   / pre  >  
 
 javscript函数如下，
 
 <   pre     lang   =  javscript >  
 function setSession（）{
 alert（document.getElementById（'hdnBtn'））; 
 
} 
 <   / pre  >  
 
但<   pre     lang   =  cs >  alert（document.getElementById（'hdnBtn'））; <   / pre  >  
 
给' null'.why？如何在usercontrol中获取按钮的ID？ 
 
谢谢

解决方案

运行代码。然后右键单击你的网页。选择viewsoruce，稍后搜索并查看带有id的你的按钮。



document.getElementById（''hdnBtn''）如果有的话会给出null不是id ''hdnBtn''。

亲爱的hasbina



尝试这个< br $>

function setSession（）{

alert（document .getElementById（''<％= hdnBtn.ClientID％>''）。Tostring（））;



}



我希望它对你有用..



谢谢和问候



Angappan.S

Hi,

Usercontrol have a button with id=hdnBtn as below,

<pre lang="asp">
&lt;%@ Control Language="C#" AutoEventWireup="true" CodeBehind="Header.ascx.cs" Inherits="M2iSTS2.UserControl.Header" %&gt;

&lt;link href="/Styles/styles.css" rel="stylesheet" type="text/css" /&gt;
&lt;script language="javascript" type="text/javascript" src="../Script/Map.js"&gt;&lt;/script&gt;

&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;

     &lt;input type="button" value="Button1" id="hdnBtn" runat="server" onserverclick="assignValue"/&gt;
 &lt;div id="header" class="header"&gt;
    &lt;h1 class="h1"&gt;TrackU: Student and Vehicle Tracking System&lt;/h1&gt;
        &lt;p class="p"&gt;&lt;a class="a" href="/Account/login.aspx"  önclick='setSession()'&gt;Logout&lt;/a&gt;&lt;/p&gt;
  &lt;/div&gt;
  &lt;div&gt;
    &lt;ul class="ul"&gt;
        &lt;li class="li"&gt;&lt;a class="lia" href="/Admin/Fleet.aspx"&gt;Fleet&lt;/a&gt;&lt;/li&gt;
        &lt;li class="li"&gt;&lt;a class="lia" href="/Admin/StudentInfo.aspx"&gt;Student Info&lt;/a&gt;&lt;/li&gt;
        &lt;li class="li"&gt;&lt;a class="lia" href="/Admin/RouteSettings.aspx"&gt;Route Settings&lt;/a&gt;&lt;/li&gt;
        &lt;li class="li"&gt;&lt;a class="lia" href="/Admin/Reports.aspx"&gt;Reports&lt;/a&gt;&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/div&gt;


</pre>

javscript function as below,

<pre lang="javscript">
function setSession() {
    alert(document.getElementById('hdnBtn'));

}
</pre>

but the <pre lang="cs">alert(document.getElementById('hdnBtn'));</pre>

giving the 'null'.why? how to get the id of button in usercontrol?

Thanks

解决方案

run the code. then right click on your webpage.select viewsoruce, later search and see ur button with id.

document.getElementById(''hdnBtn'') will gives null if there is no id as ''hdnBtn''.

Dear hasbina

try this one

function setSession() {
alert(document.getElementById(''<%=hdnBtn.ClientID%>'').Tostring());

}

I hope its useful to you..

Thanks and regards

Angappan.S

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