如何在JavaScript中检查IsPostBack ?(复制)

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How to detect/track postback in javascript? 10 answers
如何在javascript中检测/跟踪回发?10个答案

I need to run a JavaScript function onLoad(), but only do it if the page loaded the first time (i.e. is not the result of a postback).

我需要运行一个JavaScript函数onLoad()，但只有在第一次加载页面时才执行(也就是说，不是回发的结果)。

Basically, I need to check for IsPostBack in JavaScript.

基本上，我需要在JavaScript中检查IsPostBack。

Thank you.

谢谢你！

10 个解决方案

#1

Server-side, write:

服务器端,写:

if(IsPostBack)
{
   // NOTE: the following uses an overload of RegisterClientScriptBlock() 
   // that will surround our string with the needed script tags 
   ClientScript.RegisterClientScriptBlock(GetType(), "IsPostBack", "var isPostBack = true;", true);
}

Then, in your script which runs for the onLoad, check for the existence of that variable:

然后，在运行onLoad的脚本中，检查该变量是否存在:

if(isPostBack) {
   // do your thing
}

You don't really need to set the variable otherwise, like Jonathan's solution. The client-side if statement will work fine because the "isPostBack" variable will be undefined, which evaluates as false in that if statement.

你不需要设置变量，比如Jonathan的解决方案。客户端if语句将工作得很好，因为“isPostBack”变量将是未定义的，在if语句中计算为false。

#2

There is an even easier way that does not involve writing anything in the code behind: Just add this line to your javascript:

还有一种更简单的方法，不需要在后面的代码中编写任何内容:只需将这一行添加到javascript:

if(<%=(Not Page.IsPostBack).ToString().ToLower()%>){//Your JavaScript goodies here}

或

if(<%=(Page.IsPostBack).ToString().ToLower()%>){//Your JavaScript goodies here}

#3

hi try the following ...

嗨，试试下面的……

function pageLoad (sender, args) {

alert (args._isPartialLoad);

}

the result is a Boolean

结果是一个布尔值

#4

The solution didn't work for me, I had to adapt it:

解决方案对我不起作用，我不得不去适应它:

protected void Page_Load(object sender, EventArgs e)
{
    string script;
    if (IsPostBack)
    {
        script = "var isPostBack = true;";
    }
    else
    {
        script = "var isPostBack = false;";
    }
    Page.ClientScript.RegisterStartupScript(GetType(), "IsPostBack", script, true);
}

Hope this helps.

希望这个有帮助。

#5

You could put a hidden input on the page, and after the page loads, give it a value. Then you can check that field, if it was in the post data, it's a postback, otherwise it is not.

您可以在页面上放置一个隐藏的输入，在页面加载之后，给它一个值。然后你可以检查那个字段，如果它在post数据中，它是一个回发，否则它不是。

There were two solutions that used server side code (ASP.NET specific) posted as responses. I think it is worth pointing out that this solution is technology agnostic since it uses client side features only, which are available in all major browsers.

有两个解决方案使用服务器端代码(ASP)。NET specific)作为回复发布。我认为值得指出的是，这种解决方案是技术无关的，因为它只使用客户端特性，在所有主流浏览器中都是可用的。

#6

Try this, in this JS we can check if it is post back or not and accordingly do operations in the respective loops.

试试这个，在这个JS中，我们可以检查它是否返回，并相应地在各自的循环中执行操作。

    window.onload = isPostBack;

    function isPostBack() {

        if (!document.getElementById('clientSideIsPostBack')) {
            return false;
        }

        if (document.getElementById('clientSideIsPostBack').value == 'Y') {

            ***// DO ALL POST BACK RELATED WORK HERE***

            return true;
        }
        else {

            ***// DO ALL INITIAL LOAD RELATED WORK HERE***

            return false;
        }
    }

#7

You can create a hidden textbox with a value of 0. Put the onLoad() code in a if block that checks to make sure the hidden text box value is 0. if it is execute the code and set the textbox value to 1.

您可以创建一个值为0的隐藏文本框。将onLoad()代码放入if块中，该块检查以确保隐藏的文本框值为0。如果是执行代码并将textbox值设置为1。

#8

Lots of options here.

大量的选项。

For a pure JS solution, have your page submit to itself, but with additional URL parameter (mypage.html?postback=true) - you can then get the page url with window.location.href, and parse that using a split or regex to look for your variable.

对于纯JS解决方案，请将页面提交给它自己，但是要使用额外的URL参数(mypage.html?postback=true)——然后可以使用window.location来获取页面URL。使用split或regex查找您的变量，并对其进行解析。

The much easier one, assuming you sending back to some sort of scripting language to proces the page (php/perl/asp/cf et. al), is to have them echo a line of javascript in the page setting a variable:

更简单的方法是，假设您发送回某种脚本语言以推进页面(php/perl/asp/cf等)，让它们在页面中响应一行javascript，设置一个变量:

<html>

<?php
if ($_POST['myVar']) {
    //postback
    echo '<script>var postingBack = true;</script>';
    //Do other processing
} else {
    echo '<script>var postingBack = false;</script>'
 } ?>
<script>
function myLoader() {
     if (postingBack == false) {
          //Do stuff
     }
 }

<body onLoad="myLoader():"> ...

#9

Here is one way (put this in Page_Load):

这里有一种方法(将其放入Page_Load):

if (this.IsPostBack)
{
    Page.ClientScript.RegisterStartupScript(this.GetType(),"PostbackKey","<script type='text/javascript'>var isPostBack = true;</script>");
}

Then just check that variable in the JS.

然后在JS中检查这个变量。

#10

-2

Create a global variable in and apply the value

在其中创建一个全局变量并应用该值

<script>
       var isPostBack = <%=Convert.ToString(Page.IsPostBack).ToLower()%>;
</script>

Then you can reference it from elsewhere

然后你可以从其他地方引用它

#1