How can I check for IsPostBack in JavaScript? [duplicate]

Answer 1

hi try the following ...

function pageLoad (sender, args) {

alert (args._isPartialLoad);

}

the result is a Boolean

Answer 2

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

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

or

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

Answer 3

Create a global variable in and apply the value

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

Then you can reference it from elsewhere

Answer 4

Server-side, write:

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:

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.