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Uncaught TypeError: undefined is not a function - jQuery

I have problem with website slide. after clicking on inspect element in chrome i get massage
"Uncaught TypeError: undefined is not a function" in file custom.js
here is file code
jQuery(document).ready(function() {
jQuery('#slider').nivoSlider({pauseTime: 4500}); });
}
here is website address http://myisraeltoday.com using WordPress
Theme: http://wordpress.org/themes/effect
Help needed

That means that you're calling something as a function (or method), when in fact it doesn't exist. You're calling three functions:
jQuery
jQuery(document).ready
jQuery('#slider').nivoSlider
The third of these is most likely the problem.

try changing your code to this :
$(document).ready(function() {
$('#slider').nivoSlider({'pauseTime': 4500});
});
PS : Note the }); at the end not just the $

Firefox event.clientX not functioning

I'm working on a d3 and js project.
The beginning of the function looks like:
$(document).ready(function() {
d3.select("#aid").select(".abutton").on("mousemove",function() {
afile.style("top", (event.clientY+10)+"px").style("left",(event.clientX+15)+"px");
afile.html("<h3>Click text here</p><p>or here</p>");
});
I've done quite a bit of Googling!
The essence is that on mouseover, it should do the function. This works in Chrome and IE because the event variable is global, and as such so are it's client* properties.
The solution, as I understand it, is to pass in an eventObject. When I do that, my code looks like:
$(document).ready(function() {
d3.select("#aid").select(".abutton").on("mousemove",function(event) {
afile.style("top", (event.clientY+10)+"px").style("left",(event.clientX+15)+"px");
afile.html("<h3>Click text here</p><p>or here</p>");
});
The Firefox log gives me:
[09:59:04.308] TypeError: event is undefined # filepathofjavascriptfile
and similarly, it breaks in Chrome:
Uncaught TypeError: Cannot read property 'clientY' of undefined filepathofjavascriptfile
(anonymous function) help.js:34
What am I doing wrong? Please let me know if you need anything else.

Try:
d3.select("#aid").select(".abutton").on("mousemove",function() {
afile.style("top", (d3.event.clientY+10)+"px").style("left",(d3.event.clientX+15)+"px");
afile.html("<h3>Click text here</p><p>or here</p>");
});
For whatever reason, that's how d3 exposes the event object.

Uncaught TypeError: on my preloader. How to make it work?

I have always used this code to preload the pages, now I was testing it with wordpress, but I generate the following error:
  Uncaught TypeError: Property '$' of object [object Window] is not a function
The file is attached to an external file. As you can see from the demo. What am I doing wrong? Thank you :)
Used previosly
LIVE LINK
$(window).load(function() {
$(".loader").delay(350).fadeOut("slow");
})

You're calling jQuery.noConflict() from your modified copy of jQuery, so that unbinds the $ symbol.
If you're not using a conflicting library, there's no need to do that. If you remove that line, things will work. Alternatively you could wrap your preload code like this:
;(function($) {
$(window).load(function() {
$(".loader").delay(350).fadeOut("slow");
});
})(jQuery);

Undefined variable error that shouldn't be a variable

I've made a piece of code in jquery that assigns a href attribute to a variable. Here's that code:
$('#reactions' + i).attr('href', 'javascript:comments ('+entry.url+','+i+');');
This should assign a call to the javascript function comments. Now I want to use that call on a jquery mobile button, like this:
document.write('Reactions');
But doing this gives me a in FF and Chrome. This is the error from FF±
Uncaught exception: ReferenceError: Undefined variable: i_heart_chaos_ihc_after_dark_independence_day_through_a_bullhornthis_is_what
Error thrown at line 1, column 0 in javascript:comments (i_heart_chaos_ihc_after_dark_independence_day_through_a_bullhornthis_is_what,1);:
comments (i_heart_chaos_ihc_after_dark_independence_day_through_a_bullhornthis_is_what,1);
In this, i_heart_chaos_ihc_after_dark_independence_day_through_a_bullhornthis_is_what is the value of entry.url.
I'm just not getting why this error appears, as far as I know, everything should work.
I know that there are questions looking similar to mine, but I couldn't figure out the answer. If you want to see the whole source, it's here.

Surround entry.url with quotes:
$('#reactions' + i).attr('href', 'javascript:comments ("'+entry.url+'",'+i+');');

The best way to fix the issue is to do it the "jQuery way". Instead of adding a href attribute that executes JavaScript, add a click event:
$('#reactions' + i).click( function() {
comments( entry.url, i );
});
Similarly don't use document.write() but add elements to the document using jQuery functions.

jQuery $.isNumeric throws error on console

Im having a problem using an isNumeric jQuery function to check if a variable is a number.
I am getting an error
Uncaught TypeError: Object function (a,b){return new e.fn.init(a,b,h)} has no method 'isNumeric'
Here is my code
var scroll = 4;
$.isNumeric(scroll);
if (false) {
scroll = 0;
tabChange(menuTab, page, scroll);
} else {
tabChange(menuTab, page, scroll);
}
I thought this may be caused by having my code being run before jQuery has loaded but this is not the case.
Also the jQuery documentation is very unclear to me.

Which version of jQuery are you using? .isNumeric() was added in 1.7, and if you're using an earlier version it's not available, which would give that error.
Another possibility is that you have Prototype or some other JS library running as well - try using jQuery.isNumeric(scroll); instead of the $ notation.