Programming Forums > Web Development and Design > JavaScript and Client-Side Browser Scripting

FireflyX · Nov 30th, 2007, 4:37 PM

Ok just a quick question.. after sitting here for about half an hour trying to work out what's wrong with this script i come here in seek of guidence.

(Toggle Plain Text)

<script type="text/javascript">

function initialize(){ 

  var xmlHttp;
  try{
    xmlHttp = new XMLHttpRequest();    
  }catch (e){
    try{     
      xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");      
    }catch (e){      
      try{        
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");        
        }catch (e){
          alert("No ajax!");        
          return false;        
        }      
      }    
    }  
  }

function mail(){

initialize();

xmlHttp.onreadystatechange=function()
  {
  if(xmlHttp.readyState == 4)
    {
    document.getElementById("show_box").innerHTML = xmlHttp.responseText;
    }
  }

xmlHttp.open("GET","http://www.staticfire.co.uk/ajaxrequest.php?cmd=mail",true);
xmlHttp.send(null);

}

</script>

The problem seems to be that it isn't recognising the initialize() function. But if i replace where i call the function with the code for that function it all runs fine. Am i missing something obvious here?

-Thanks, Firefly

titaniumdecoy · Nov 30th, 2007, 5:00 PM

Try replacing the call to initialize() with window.onload = initialize;.

FireflyX · Nov 30th, 2007, 5:27 PM

Thanks for the reply but that didn't seem to make a difference. I can fix the problem by just putting the code for that function in each time i wish to use it but that seems very inconvinient

Sane · Dec 1st, 2007, 7:16 PM

Try moving var xmlHttp; outside the scope of the function. Make it the first line of the code, and not within the function call. I think that's because mail() refers to xmlHttp, but xmlHttp expires once initialize() ends.

FireflyX · Dec 1st, 2007, 7:41 PM

you know what.. that just worked! Thanks for the help my site now has a pm system with no page reloads

Dameon · Dec 1st, 2007, 7:53 PM

Sane is correct...O great PHP god

I'd suggest the Firebug extension for Firefox (includes javascript debugging, a javascript command line, and can show ajax requests real time, among other things). This would have told you that initialize() was actually getting called.

It would also be much less painful to use a library such as prototype or jQuery

jQuery equivalent looks something like this.
Warning: Untested.

 javascript Syntax (Toggle Plain Text) 
$('#myAwesomeButtonID').click(
	function() {
		$('#show_box').load('/kickass_script.php', 
                       { mysteriousParameter: 42 });
		//Prevent the button from triggering form submission
		return false;
	});
$('#myAwesomeButtonID').click(
	function() {
		$('#show_box').load('/kickass_script.php', 
                       { mysteriousParameter: 42 });
		//Prevent the button from triggering form submission
		return false;
	});

FireflyX · Dec 1st, 2007, 9:04 PM

Quote:

Sane is correct...O great PHP god

heh, i just wish i was the god of ajax right now

Perhaps i should look at getting this Firebug extension you speak of as it sounds like it could be useful.

Sane · Dec 2nd, 2007, 7:16 AM

Yep. I use that (although I didn't have to in this case). Mine's called the Web Developer extention, very handy. But Dameon could be referring to something similar.

FireflyX · Dec 5th, 2007, 4:58 PM

Hi again sorry to bump this thread back up but i thought this was working fine till a friend told me he was getting errors from it. I tested the system on a few browsers and it was fine on IE7, Opera and Safari but on Firefox and Netscape it just comes up with "Length required". Can anyone tell me why this might happen? Thanks

The Dark · Dec 5th, 2007, 6:08 PM

You should mention the actual URL so we could look at it not working, or if it is a private page, post your current code. Also, the line number of the error would be a help.

Nov 30th, 2007, 4:37 PM	#1
FireflyX PHP God Join Date: Nov 2007 Location: Stockton, England Posts: 15 Rep Power: 0	Problem with calling a function Ok just a quick question.. after sitting here for about half an hour trying to work out what's wrong with this script i come here in seek of guidence. (Toggle Plain Text) <script type="text/javascript"> function initialize(){ var xmlHttp; try{ xmlHttp = new XMLHttpRequest(); }catch (e){ try{ xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); }catch (e){ try{ xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); }catch (e){ alert("No ajax!"); return false; } } } } function mail(){ initialize(); xmlHttp.onreadystatechange=function() { if(xmlHttp.readyState == 4) { document.getElementById("show_box").innerHTML = xmlHttp.responseText; } } xmlHttp.open("GET","http://www.staticfire.co.uk/ajaxrequest.php?cmd=mail",true); xmlHttp.send(null); } </script> <script type="text/javascript"> function initialize(){ var xmlHttp; try{ xmlHttp = new XMLHttpRequest(); }catch (e){ try{ xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); }catch (e){ try{ xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); }catch (e){ alert("No ajax!"); return false; } } } } function mail(){ initialize(); xmlHttp.onreadystatechange=function() { if(xmlHttp.readyState == 4) { document.getElementById("show_box").innerHTML = xmlHttp.responseText; } } xmlHttp.open("GET","http://www.staticfire.co.uk/ajaxrequest.php?cmd=mail",true); xmlHttp.send(null); } </script> The problem seems to be that it isn't recognising the initialize() function. But if i replace where i call the function with the code for that function it all runs fine. Am i missing something obvious here? -Thanks, Firefly

Nov 30th, 2007, 5:00 PM	#2
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 837 Rep Power: 3	Re: Problem with calling a function Try replacing the call to initialize() with `window.onload = initialize;`.

Nov 30th, 2007, 5:27 PM	#3
FireflyX PHP God Join Date: Nov 2007 Location: Stockton, England Posts: 15 Rep Power: 0	Re: Problem with calling a function Thanks for the reply but that didn't seem to make a difference. I can fix the problem by just putting the code for that function in each time i wish to use it but that seems very inconvinient

Dec 1st, 2007, 7:16 PM	#4
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	Re: Problem with calling a function Try moving `var xmlHttp;` outside the scope of the function. Make it the first line of the code, and not within the function call. I think that's because `mail()` refers to `xmlHttp`, but `xmlHttp` expires once initialize() ends.

Dec 1st, 2007, 7:41 PM	#5
FireflyX PHP God Join Date: Nov 2007 Location: Stockton, England Posts: 15 Rep Power: 0	Re: Problem with calling a function you know what.. that just worked! Thanks for the help my site now has a pm system with no page reloads

Dec 1st, 2007, 7:53 PM	#6
Dameon Troll Join Date: Apr 2005 Location: Texas Posts: 732 Rep Power: 4	Re: Problem with calling a function Sane is correct...O great PHP god I'd suggest the Firebug extension for Firefox (includes javascript debugging, a javascript command line, and can show ajax requests real time, among other things). This would have told you that initialize() was actually getting called. It would also be much less painful to use a library such as prototype or jQuery jQuery equivalent looks something like this. Warning: Untested. javascript Syntax (Toggle Plain Text) $('#myAwesomeButtonID').click( function() { $('#show_box').load('/kickass_script.php', { mysteriousParameter: 42 }); //Prevent the button from triggering form submission return false; }); $('#myAwesomeButtonID').click( function() { $('#show_box').load('/kickass_script.php', { mysteriousParameter: 42 }); //Prevent the button from triggering form submission return false; }); __________________ MD5(sig) = bcef75433db02e9ad9bf81d6f7c5c270 Last edited by Dameon; Dec 1st, 2007 at 8:15 PM.

Dec 2nd, 2007, 7:16 AM	#8
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	Re: Problem with calling a function Yep. I use that (although I didn't have to in this case). Mine's called the Web Developer extention, very handy. But Dameon could be referring to something similar.

Dec 5th, 2007, 4:58 PM	#9
FireflyX PHP God Join Date: Nov 2007 Location: Stockton, England Posts: 15 Rep Power: 0	Re: Problem with calling a function Hi again sorry to bump this thread back up but i thought this was working fine till a friend told me he was getting errors from it. I tested the system on a few browsers and it was fine on IE7, Opera and Safari but on Firefox and Netscape it just comes up with "Length required". Can anyone tell me why this might happen? Thanks __________________ mysql_query("DELETE chavs FROM earth") or die("chavs");

Dec 5th, 2007, 6:08 PM	#10
The Dark Expert Programmer Join Date: Jun 2005 Posts: 816 Rep Power: 4	Re: Problem with calling a function You should mention the actual URL so we could look at it not working, or if it is a private page, post your current code. Also, the line number of the error would be a help.

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Programming Forums > Web Development and Design > JavaScript and Client-Side Browser Scripting

Problem with calling a function