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Functionally, in this case, there is no real effective difference in their behaviour as far as the end result goes. Historically, eval has been a real resource hog because it would start up a new instance of the JS compiler (similarly, the same issue as setTimeout or setInterval), but newer JS compilers have become much better at caching the eval compilation so this overhead isn't as bad.
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Pete O'Hanlon wrote: Functionally, in this case, there is no real effective difference in their behaviour as far as the end result goes
There is one difference, which this example demonstrates:
<html>
<head>
<title>Eval / setTimeout</title>
<script type="text/javascript">
</script>
</head>
<body>
<div id="myDiv">unchanged</div>
</body>
</html>
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AspDotNetDev wrote: // Uncomment one of the below lines... one will work and one will not.
I didn't get your point here. Of course the un-commented line will work and the commented won't. 
..Go Green..
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Lol, I'm not sure if you are joking. What I meant was, uncomment one line at a time. That leaves two scenarios. Only one of those scenarios will function properly. More specifically, the scenario in which you uncomment the eval line will not function. The scenario in which you uncomment the setTimeout line will function properly.
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No, I wasn't joking. I just tested it. The eval one is not working. I haven't used eval ever, so I didn't know about it, until now. 
Thanks!
..Go Green..
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Yeah, the reason eval doesn't work is because "myDiv" isn't created yet, and eval tries to immediately evaluate code that references that element. Using setTimeout seems to put the function call onto a procession queue so that it gets called once the current operation (loading the HTML) is complete.
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AspDotNetDev wrote: <layer>Yeah, the reason eval doesn't work is because "myDiv" isn't created yet, and eval tries to immediately evaluate code that references that element.
Correct! And if you move the script after the body tag, both will work.
AspDotNetDev wrote: Using setTimeout seems to put the function call onto a procession queue so that it gets called once the current operation (loading the HTML) is complete.
Yeah, it seems the function is executed only after the whole HTML is loaded.
..Go Green..
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"eval" will execute "somecode()" right away. "setTimeout" will execute "somecode()" at a later time (even with the duration set to 0).
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How later?
Help people,so poeple can help you.
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I am not sure exactly, but I think it will execute next chance it gets (i.e., after the current processing is complete). So, for example, if the page is still loading, the JavaScript will run after the page has loaded.
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ok, sir;
i have used setTimeout() with 0 time to call client method when a message box dialog got closed. actualy i am not good in javascript, but i sow that call in some web resources used in ajax controls toolkit for asp.net.
plaese take a look at my article of Message Box Control[^] and tell me what do you think;
regards;
Help people,so poeple can help you.
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Hi ,
I on button click I open a jquery modal with iframe which loads another aspx page.
Now this other aspx page makes a call to webservice and then loads data. I have the service call on the page load of this page.
So there a gap between the modal window opens and the data load in it.
How can I implement a wait gif or just a text like say 'processing' till the data loads?
Thanks
My code is as below
<div id="mydiv" >
<iframe id ="popup" width ="100%" height="50%"></iframe>
</div>
jquery/javascript
function openDialog() {
var url = "test.aspx?NAME=" + encodeURIComponent($("#<%=txtName.ClientID %>").val());
$("#popup").attr("src", url);
$("#mydiv").dialog('open');
}
$(document).ready(function() {
$("#mydiv").dialog({
autoOpen: false,
modal: true,
width: 500,
scroll: true
});
});
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You don't really need to use an iframe in this instance, at least that I can see. iframes are typically used to display content from a different source, like a different URL. You can simply replace the the HTML content of the div. That would give you more control over the process
The general idea is
function openDialog()
{
$("#wait").show();
$.ajax({
url: "test.aspx?NAME=" + encodeURIComponent($("#<%=txtName.ClientID %>").val());,
success: complete;
}
});
}
function complete(result)
{
$("#wait").hide();
$("#mydiv").html(result);
}
I know the language. I've read a book. - _Madmatt
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I have a problem and i can't figure out why th setTimeout function in this object doesn't tick...
Everything else work just fine but the no ticking. I've struggled with this almost all day but
i ca'nt get the setTimeout working...
Please u wiser ones, hjälp mej...auttakaa minua...help me...
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript" src="js/prototype.js"></script>
<script type="application/javascript">
<!--
var objIdCnt = 0;
var objIdPre = "progressBar";
var ProgressBar = Class.create({
initialize: function(Container) {
this.Container = Container;
this.Id = objIdPre + objIdCnt++;
this.Type = 1;
this.Interval = 100;
this.Step = 2;
this.Stopped = true;
this.Min = 0;
this.Max = 100;
this.Position = 50;
this.Width = 100;
this.Left = 10;
this.Top = 10;
this.Visible = false;
this.t;
this.IncDecTotal = 0;
this.IncDec = 0;
this.ValTo = 0;
},
create : function(position, value)
{
if(this.Container == null)
{
alert("No container.");
}
else
{
var progBarImage;
progBarImage = document.createElement('IMG');
progBarImage.setAttribute("id", this.Id);
progBarImage.src = "img/Frame_200x16.png";
progBarImage.style.backgroundRepeat = "no-repeat";
this.Width = progBarImage.width;
progBarImage.style.backgroundPosition =
-(this.Width - (this.Position - this.Min) /(this.Max - this.Min) * this.Width) + "px 0px";
this.Container.appendChild(progBarImage);
this.Container.style.position = "absolute";
this.Container.style.left = this.Left + "px";
this.Container.style.top = this.Top + "px";
this.setType(value);
this.setPosition(position);
}
},
hide : function()
{
$(this.Id).style.visibility = "hidden";
},
show : function()
{
$(this.Id).style.visibility = "visible";
},
setPosition : function(position)
{
this.Position = position;
if(position > this.Max)
{
this.Position = this.Max;
clearTimeout(this.t);
}
if(position < this.Min)
{
this.Position = this.Min;
clearTimeout(this.t);
}
$(this.Id).style.backgroundPosition =
-(this.Width - (this.Position - this.Min) / (this.Max - this.Min) * this.Width) + "px 0px";
},
setType : function(value)
{
switch(value)
{
case 1: $(this.Id).style.backgroundImage = "url(img/RedBar_400x16.png)";
break;
case 2: $(this.Id).style.backgroundImage = "url(img/GreenBar_400x16.png)";
break;
case 3: $(this.Id).style.backgroundImage = "url(img/BlueBar_400x16.png)";
break;
}
},
doAnimate : function(value)
{
if(this.Position == value)
{
return;
}
this.IncDecTotal = 0;
this.ValTo = value;
this.IncDec = this.Step;
if(this.Position > value)
{
this.IncDec = -this.Step;
}
this.Stop = false;
this.timedAnimate();
},
timedAnimate : function()
{
this.setPosition(this.Position + this.IncDec);
if((this.IncDec < 0) && (this.Position <= this.ValTo))
{
clearTimeout(this.t);
this.Stop = true;
}
else if((this.IncDec > 0) && (this.Position >= this.ValTo))
{
clearTimeout(this.t);
this.Stop = true;
}
else
{
this.t = setTimeout("this.timedAnimate()", this.Interval);
}
},
sleep : function(delay)
{
var start = new Date().getTime();
var cur = start
while(cur - start < delay)
{
cur = new Date().getTime();
}
}
});
-->
</script>
</head>
<body>
<div id="progBar0"></div>
<br />
<input type="button" value="+5" onclick="progress0.setPosition(progress0.Position + 5);" />
<input type="button" value="-5" onclick="progress0.setPosition(progress0.Position - 5);" />
<div id="progBar1"></div>
<div id="progBar2"></div>
<script type="application/javascript">
<!--
var progress0 = new ProgressBar($("progBar0"));
var progress1 = new ProgressBar($("progBar1"));
var progress2 = new ProgressBar($("progBar2"));
progress0.create(25, 1);
progress1.Top = progress0.Top + 50;
progress1.create(50, 2);
progress2.Top = progress1.Top + 50;
progress2.create(75, 3);
progress1.doAnimate(100);
-->
</script>
</body>
</html>
</code>
If u want the images for testing, just ask...i'm glad to send them.
GBY:Olli.
Do u want to be always right or do u want to be happy...
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Instead of this:
setTimeout("this.timedAnimate()", this.Interval);
Do this:
setTimeout(this.timedAnimate, this.Interval);
With your version, you are passing in a string, which gets evaluated when setTimeout runs your code rather than when you call setTimeout. So, "this" refers to a different scope/context. The solution is to pass in the actual function you want to be called.
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I tried but it didn't worked...is the 'this' pointing window object rather than the object
i've created, if so do i have to move the timed animate to global or can i somehow other
way point it to window.setTimeout method?
I tried also use of closure attribute like setTimeout(function() { timedAnimate(); }, this.Interval),
but noo-ou-ou nothing happened.
i tried like this:
doAnimate : function(value)
{
if(this.Position == value)
{
return;
}
this.IncDecTotal = 0;
this.ValTo = value;
this.IncDec = this.Step;
if(this.Position > value)
{
this.IncDec = -this.Step;
}
alert("this: " + this + " this.IncDec: " + this.IncDec);
this.Stop = false;
this.timedAnimate();
},
timedAnimate : function()
{
this.setPosition(this.Position + this.IncDec);
if((this.IncDec < 0) && (this.Position <= this.ValTo))
{
clearTimeout(this.t);
this.Stop = true;
}
else if((this.IncDec > 0) && (this.Position >= this.ValTo))
{
clearTimeout(this.t);
this.Stop = true;
}
else
{
this.t = setTimeout(timedAnimate, this.Interval);
}
},
</code>
Olli.
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Instead of this:
this.t = setTimeout(timedAnimate, this.Interval);
Try this:
this.t = setTimeout(this.timedAnimate, this.Interval);
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I'll try that but meanwhile i moved the function to global scope and i pass the object to it. It works just fine but
it's not -in- the object so it ruins my OO way of thinking... (i'm mainly C++ programmer and JScript is new to me).
I made it like this:
function timedAnimate(elementId)
{
if(elementId.Stop == true)
{
return;
}
elementId.setPosition(elementId.Position + elementId.IncDec);
if((elementId.IncDec < 0) && (elementId.Position <= elementId.ValTo))
{
clearTimeout(elementId.t);
elementId.Stop = true;
}
else if((elementId.IncDec > 0) && (elementId.Position >= elementId.ValTo))
{
clearTimeout(elementId.t);
elementId.Stop = true;
}
else
{
elementId.t = setTimeout(function() { timedAnimate(elementId) }, elementId.Interval);
}
};
</code>
Olli.
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Hi all,
I've kind of design where once an item is selected from a dropdownlist (HTML select) a new dropdown list is displayed with relevant items. It can be upto another level too. For example, say I've a dropdown to select the country. Once I choose the country relevant cities are displayed in another dropdown list below the original one. Once a city is selected from new list, hotels is displayed in that list.
Now say I submit the form and do the process. That part is fine. But once user click back button (to come back to that dorpdown lists page) I want to preserve user selections.
Any idea that how to do it.
All the lists generated with AJAX calls. Since dynamically generated list from the second level I cannot do with JS, using getElementByID() i cannot find them.
Comments really appreciate.
Thanks in advance
I appreciate your help all the time...
CodingLover
modified on Thursday, May 5, 2011 11:58 PM
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Hi
May be this would be helpful.
1. before navigating from Dropdown page to another page you should save all the Three selected values (Country, City and Hotel in hidden field).
2. When you will get back then check is hidden field contain value.
3. Execute process one by one like
first get the Countries using AJAX call and set selected values according to Hidden field value.
and so on for the hotel...
The above is algorithm and i am not sure it is work or not but you may try something like that.
Thanks,
Imdadhusen
sunaSaRa Imdadhusen
+91 99095 44184
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Thanks for the comment.
Actually what I've done was pass URL parameters with pre-define conding mechanism in my application. Your suggestion is worth to try, but I've already done it in that way. I'll give a try later on your suggestion.
Thanks again.
I appreciate your help all the time...
CodingLover
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How status bar can be refreshed inside a loop? Is it even possible?
for(i = 0; i < items.length; i++ )
{
if(items[i]._category == category)
{
window.status = ('fillItemContent()' + ": " + i);
.
.
.
}
}
That doesn't work.
Olli.
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status will probably not update as the message pump will not release until the loop stops and functions exit.
This is the same for windows forms etc.
I don't think you can force a refresh as you can with forms apps either.
One option might be to update a shared variable and then set up a timer that update the status based on the shared variable value and then the timer retriggers its next update timer tick. Use a flag to determine if the timer should continue to update or not.
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I'm new with JScript, i'm C, C++ coder. Would u be kind enough to show me an little example. So, i make global variable or pass variable to setTimeOut method and update the status bar in there - or...what? The goal i want is to show load progression in status bar...and just practicing for fun...
Olli.
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