Hi,
i know we can wirte a userdefined callback function..
I had a try for a long time though i feel im near but not able to coin out the exact thing. can any body tell me about a user defined callback function... and a sample on how to write it...
looking forward for a reply..
Thanks in advance for your reply...
6 3165 pbmods 5,821
Recognized Expert Expert
Heya, New Learner.
You may find this article useful.
Heya, New Learner.
You may find this article useful.
thx pbmods... The article was useful...
but my doubt is..
whenever http.onreadysta techange value is changed the assigned function is called...
similarly.. i need to create a userdefined handler for ex:
x = somefunction
like onreadystatecha nge(which is a browser object) whenever the value of x is changed thn somefunction should be initiated.
Is this Possible..
looking forward for a reply..
Thanks in advance
gits 5,390
Recognized Expert Moderator Expert
hi ...
so x is a simple js-variable and you want to react with 'somefunction' when the value of x changes?
but i assume you already know WHERE x changes (in case its your own code)? ... everytime a value is assigned to x you may call 'somefunction' or use a set-function for x instead of a simple assignment ... and in that so called 'setter' you may call whatever you want ...
hope i didn't misunderstood your problem?
another method would be to define a watcher: - obj.watch(property, callback);
-
and to detach the watcher:
kind regards
hi ...
so x is a simple js-variable and you want to react with 'somefunction' when the value of x changes?
but i assume you already know WHERE x changes (in case its your own code)? ... everytime a value is assigned to x you may call 'somefunction' or use a set-function for x instead of a simple assignment ... and in that so called 'setter' you may call whatever you want ...
hope i didn't misunderstood your problem?
another method would be to define a watcher: - obj.watch(property, callback);
-
and to detach the watcher:
kind regards
tnx for the idea...
I have tried out the way u suggested ... it works fine...
But my doubt is...
we write: - http.onreadystatechange=response;
response is triggered whenever onreadystatecha nge is chnged from 0 .. 4.
similarly... i write - function base() {
-
this.x=0;
-
}
-
-
base = new base()
-
-
function tst(){
-
base.x = callfun;
-
}
in a html page i have 2 buttons
on a 1st onclick event i say base.x=1// I need callfun to be triggered (coz x has changed)
on a 2nd onclick event i say base.x=2// I need callfun to be triggered (coz x has changed)
Is This possible...?
Looking for ward fir a reply..
Thanks in advance
acoder 16,027
Recognized Expert Moderator MVP
Please use CODE tags when posting code, e.g.
[code=javascript]Javascript code goes here[/code.] (remove the dot).
gits 5,390
Recognized Expert Moderator Expert
hi ...
have a look at the following example: - <script>
-
function OBJ() {
-
this.x = 0;
-
}
-
-
OBJ.prototype.increment_val = function() {
-
this.x++;
-
}
-
-
var obj = new OBJ;
-
-
obj.watch('x', function(val, oldval, newval) {alert(newval); return newval;});
-
</script>
-
-
<a href="#" onclick="obj.increment_val();">increase obj counter</a>
-
kind regards
ps: note watch will not work with IE ... so the 'setter'-method is probably to be preferred :)
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