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Why does .myFunction() not work the way I think it should? [duplicate]

Suppose I need to declare a JavaScript variable based on a counter, how do I do so?
var pageNumber = 1;
var "text"+pageNumber;
The above code does not work.

In JavaScript (as i know) there are 2 ways by which you can create dynamic variables:
eval Function
window object
eval:
var pageNumber = 1;
eval("var text" + pageNumber + "=123;");
alert(text1);
window object:
var pageNumber = 1;
window["text" + pageNumber] = 123;
alert(window["text" + pageNumber]);

How would you then access said variable since you don't know its name? :) You're probably better off setting a parameter on an object, e.g.:
var obj = {};
obj['text' + pageNumber] = 1;
if you -really- want to do this:
eval('var text' + pageNumber + '=1');

I don't think you can do it sing JavaScript.I think you can use an array instead of this,
var textArray=new Array();
textArray[pageNumber]="something";

Assuming that the variable is in the global scope, you could do something like this:
var x = 1;
var x1 = "test"
console.log(window["x" + x]); //prints "test"
However, a better question might be why you want such behaviour.

You could also wrap your counter in an object:
var PageNumber = (function() {
var value = 0;
return {
getVal: function(){return value;},
incr: function(val){
value += val || 1;
this['text'+value]=true /*or some value*/;
return this;
}
};
})();
alert(PageNumber.incr().incr().text2); //=>true
alert(PageNumber['text'+PageNumber.getVal()]) /==> true

It can be done using this keyword in JS:
Eg:
var a = [1,2,3];
for(var i = 0; i < a.length; i++) {
this["var" + i] = i + 1;
}
then when you print:
var0 // 1
var1 // 2
var2 // 3

I recently needed something like this.
I have a list of variables like this:
var a = $('<div class="someHtml"></div>'),b = $('<div class="someHtml"></div>'),c = $('<div class="someHtml"></div>');
I needed to call them using another variable that held a string with the name of one of these variables like this:
var c = 'a'; // holds the name of the wanted content, but can also be 'b' or 'c'
$('someSelector').html(eval(c)) // this will just use the content of var c defined above
Just use eval to get the variable data.
I just did

I know a lot of the other answers work great, such as window["whatever"] = "x"; but I will still put my own answer here, just in case it helps.
My method is to use Object.assign:
let dict = {};
dict["test" + "x"] = "hello";
Object.assign(window, dict)

a little improvement over bungdito's answer, use the dynamic variable dynamically
var pageNumber = 1;
eval("var text" + pageNumber + "=123456;");
eval(`alert(text${pageNumber})`);
note: usage of eval is strongly discourgae

Jquery insert function params into selector

I have a Jquery function that helps with validation over 1 object. I need to expand it so that the function will run over 3 different objects. I am trying to define a function that takes a parameter(whichquote) to insert the appropriate object in the function. Here is my code. What I am doing wrong? I assume I do not have the selector correct as the code works if I put it in.
Original Function that works:
var depends = function() {
var selectorD = $("input[name^='lead[quote_diamonds_attributes]'], select[name^='lead[quote_diamonds_attributes]']");
var vals = '';
selectorD.not(':eq(0)').each(function () {
vals += $(this).val();
});
return vals.length > 0;
};
Function I am trying to create that allows me to use it on other objects. This currently does not work.
var depends = function(whichquote) {
var selectorD = $("input[name^='lead[+ whichquote +]'], select[name^='lead[+ whichquote +]']");**
var vals = '';
selectorD.not(':eq(0)').each(function () {
vals += $(this).val();
});
return vals.length > 0;
};
I think the problem is with my concating in the var selectorD but cannot seem to get the syntax correct.

Your selector isn't actually inputting whichquote because the string concatenation is incorrect.
Try
var selectorD = $("input[name^='lead[" + whichquote + "]'], select[name^='lead[" + whichquote +"]']");

How to get the next element of an array with Jquery onclick

Hi all i am trying to change the html of an object from an array of htmls. But i am having problem iterating properly. I managed to make it work once
EDIT
After a few complains about the clarity of my question I will rephrase it. I have a div panel called .trpanel and a button called #trigger2 (it is a next button). Then I have a series of divs with texts that contain translations. I want when I press the button (called next) to cycle through the translations one by one on the trpanel.
var ltranslation = [];
ltranslation[0] = $("#translation-en-1").html();
ltranslation[1] = $("#translation-ur-en").html();
ltranslation[2] = $("#translation-fr-en").html();
ltranslation[3] = $("#translation-it-en").html();
ltranslation[4] = $("#translation-sp-en").html();
ltranslation[5] = $("#translation-po-en").html();
ltranslation[6] = $("#translation-fr-en").html();
ltranslation[7] = $("#translation-de-en").html();
var l= ltranslation;
$("#trigger2").off('click').on('click',function(){
for (var i = 0; i <= ltranslation.length; i++){
if (i==7){i=0;}
$(".trpanel").html.ltranslation[i]; or ???//replace().ltranslation[]+i??? the code throws errors
}
});
I am quite new to Javascript and i am getting a bit confused with the types of objects and arrays and loops. I managed once to add the htmls but without replacing them ... so they all came one after the other. The i tried to change the code and it hasn't worked since. Any help will be greatly appreciated.

A lot of guessing, but seems like you are trying to do this :
var trans = $('[id^="translation-"]'),
idx = 0;
$("#trigger2").on('click',function(){
$(".trpanel").html( trans.eq(idx).html() );
idx = idx > 6 ? 0 : idx+1;
});
FIDDLE

I think you are trying to do this:
if (i == 7) {
i = 0; // I don't really know why you are doing this, but it will reset the loop
}
$(".trpanel").html(ltranslation[i]); //I'm passing ltranslation[i] to the html method. Instead of .html.ltranslation[i].
}
Also, without seeing any html, I'm not sure but I think you may want to iterate over .trpanel ?
Something like:
$(".trpanel").eq(i).html(ltranslation[i]);
Another thing (so you can make your code clearer I think). You can abstract the array population in a function, like this:
var ltranslation = [];
var languages = ["en-1", "ur-en", "fr-en", "it-en", "sp-en", "po-en", "fr-en", "de-en"];
$.each(languages, function(index) {
ltranslation[index] = $("#translation-" + this).html();
});
// Then you can use ltranslation

If you want to flip through several translations I would implement it that way:
var translations=["hej","hello", "hallo","hoy"];
var showTranslation=function(){
var current=0;
var len=translations.length;
return function(){
var direction=1;
if (current>=len) current=0;
$("#text").text(translations[current]);
current+=direction;
}
}();
$("#butt").on("click", showTranslation);
Fiddle: http://jsfiddle.net/Xr9fz/
Further: You should give your translations a class, so you could easily grab all of them with a single line:
$(".translation).each(function(index,value){ ltranslation.push(value); })

From the question : I managed once to add the htmls but without replacing them -
I think you want to add all of these items into $(".trpanel"). First, dont take the HTML of each element, clone the element itself :
//method ripped from Nico's answer.
var ltranslation = [];
var languages = ["en-1", "ur-en", "fr-en", "it-en", "sp-en", "po-en", "fr-en", "de-en"];
$.each(languages, function(index) {
ltranslation[index] = $("#translation-" + this).clone();
});
Then you could append everything into the container, so add the htmls but without replacing them. append takes in an array without replacing the previous html.
$("#trigger2").off('click').on('click',function() {
$(".trpanel").append(ltranslation);
});

I don't know what exactly you're tring to do, but I've put comments in your code to help you better understand what your code is doing. The net effect of your code is this (which I doubt you want) :
$("#trigger2").off('click').on('click',function(){
$(".trpanel").html(ltranslation[7]);
});
This is your code with some comments and minor changes
var ltranslation = [];
ltranslation[0] = $("#translation-en-1").html();
ltranslation[1] = $("#translation-ur-en").html();
ltranslation[2] = $("#translation-fr-en").html();
ltranslation[3] = $("#translation-it-en").html();
ltranslation[4] = $("#translation-sp-en").html();
ltranslation[5] = $("#translation-po-en").html();
ltranslation[6] = $("#translation-fr-en").html();
ltranslation[7] = $("#translation-de-en").html();
var l= ltranslation;
$("#trigger2").off('click').on('click',function(){
for (var i = 0; i < ltranslation.length; i++){
//if (i==7){i=0;} <-- This will cause an infinite loop won't it? are you trying to reset i? i will reset next time loop is called,
$(".trpanel").html(ltranslation[i]); //<-- this will overwrite elements with class .trpanel ltranslation.length times...
///you'll see only the value of translation[7] in the end
}
});
EDIT
To do what you want to do based on your comments, try this:
var ltranslation = [];
ltranslation[0] = $("#translation-en-1").html();
ltranslation[1] = $("#translation-ur-en").html();
ltranslation[2] = $("#translation-fr-en").html();
ltranslation[3] = $("#translation-it-en").html();
ltranslation[4] = $("#translation-sp-en").html();
ltranslation[5] = $("#translation-po-en").html();
ltranslation[6] = $("#translation-fr-en").html();
ltranslation[7] = $("#translation-de-en").html();
var counter = 0;//a global counter variable
$("#trigger2").click(function(){ //eeverytime button is clicked do this
$(".trpanel").html(ltranslation[counter]); //set the html to an element of array
counter++; //increment counter
if(counter==ltranslation.length) //reset the counter if its bigger than array len
counter=0;
});

Using Javascript to dynamically create dom elements with incrementing ID's

I have a div with an ID "orangeButton" and each time you click on it it creates a new div. This works fine but... I want each newly created div to have an incremental number added to it's ID.
I am not sure how to do this.
Here is a fiddle of the code I have thus far with comments.
http://jsfiddle.net/taoist/yPrab/1/
Thank you
Javascript Code
var applicationArea = document.getElementById("applicationArea");
var orangeButton = document.getElementById("orangeButton");
orangeButton.onclick = function() {
var newDivThingy = document.createElement("div");
newDivThingy.id = 'newDivThingy'; // I want each newly created div to have a numeric value concatenated to it's ID. IE newDivThingy1 newDivThingy2 newDivThingy3
applicationArea.appendChild(newDivThingy);
};​

Am I missing something, why not use a counter?
var counter = 0;
button.onclick = function(){
var newDivThingy = document.createElement("div");
newDivThingy.id = 'newDivThingy' + (++counter);
// continue your stuff here
}

Libraries like underscorejs provide a uniqueid function for this. Otherwise its easy to implement one.
myNamespace.uniqueId = (function () {
var counter = 0; // in closure
return function (prefix) {
counter++;
return (prefix || '') + '-' + counter;
};
}());
Usage.
newDiv.id = myNamespace.uniqueId('newDiv');

Simply use a integer and increment it as each element is added.
var applicationArea = document.getElementById("applicationArea"),
orangeButton = document.getElementById("orangeButton"),
counter = 1;
orangeButton.onclick = function() {
var newDivThingy = document.createElement("div");
newDivThingy.id = "newDivThingy" + counter++;
applicationArea.appendChild(newDivThingy);
}

I have no doubt you have solution and may have forgotten this post.
BUT, I wold like to show a solution that is a compact format.
Note the counter is set to (counter++) so it will start at 1.
var orangeButton = document.getElementById("orangeButton");
var counter = 0;
orangeButton.onclick = function() {
document.getElementById('applicationArea')
.appendChild(document.createElement('div'))
.setAttribute("id", 'newDivThingy' + counter++);
// I want each newly created div to have a
// numeric value concatenated to it's ID.
// IE newDivThingy1 newDivThingy2 newDivThingy3
};​

Use "event's" output as a variable

I have a problem to manipulate checkbox values. The ‘change’ event on checkboxes returns an object, in my case:
{"val1":"member","val2":"book","val3":"journal","val4":"new_member","val5":"cds"}
The above object needed to be transformed in order the search engine to consume it like:
{ member,book,journal,new_member,cds}
I have done that with the below code block:
var formcheckbox = this.getFormcheckbox();
formcheckbox.on('change', function(checkbox, value){
var arr=[];
for (var i in value) {
arr.push(value[i])
};
var wrd = new Array(arr);
var joinwrd = wrd.join(",");
var filter = '{' + joinwrd + '}';
//console.log(filter);
//Ext.Msg.alert('Output', '{' + joinwrd + '}');
});
The problem is that I want to the “change” event’s output (“var filter” that is producing the: { member,book,journal,new_member,cds}) to use it elsewhere. I tried to make the whole event a variable (var output = “the change event”) but it doesn’t work.
Maybe it is a silly question but I am a newbie and I need a little help.
Thank you in advance,
Tom

Just pass filter to the function that will use it. You'd have to call it from inside the change handler anyway if you wanted something to happen:
formcheckbox.on('change', function(cb, value){
//...
var filter = "{" + arr.join(",") + "}";
useFilter(filter);
});
function useFilter(filter){
// use the `filter` var here
}

You could make filter a global variable and use it where ever you need it.
// global variable for the search filter
var filter = null;
var formcheckbox = this.getFormcheckbox();
formcheckbox.on('change', function(checkbox, value){
var arr = [],
i,
max;
// the order of the keys isn't guaranteed to be the same in a for(... in ...) loop
// if the order matters (as it looks like) better get them one by one by there names
for (i = 0, max = 5; i <= max; i++) {
arr.push(value["val" + i]);
}
// save the value in a global variable
filter = "{" + arr.join(",") + "}";
console.log(filter);
});