Set JS Variable to href of clicked anchor dynamically - javascript

I need to set a variable's value based on the href of a clicked link.
I know that I can set the variable using an event listener that would run this when the link is clicked
var x = document.getElementById("myAnchor").href
But that is set to a single element. I need it to work dynamically based on which link is clicked. For example:
Partner A
Partner B
Partner C
// function to attach click event to all links
function attachClickEvent() {
var linklist = document.getElementsByTagName('a');
var listLength = linklist.length;
var i = 0;
for (; i < listLength; i++) {
linklist[i].addEventListener("click", ClickedLinkEvent);
}
}
window.onload = attachClickEvent;
// function that creates click event
function ClickedLinkEvent() {
var anchor = obj.href;
console.log(anchor);
if (anchor.includes('clientdomain')) {
//do nothing
} else {
SendLinkEvent();
}
}
// function to run on click event
function SendLinkEvent() {
ga('send', {
hitType: 'event',
eventCategory: 'Affiliate Link',
eventAction: 'Click',
eventLabel: anchor
});
}
The anchor variable needs to be set to /link1 if Partner A is clicked, but /link2 if Partner B is clicked.
So, is there a way to do this with vanilla JS?

If you adjust the ClickedLinkEvent method declaration and add an argument to the method signature, then you will have the event object. The event object has a target parameter. If I understood you correctly, this is what you need. Don't you?
function ClickedLinkEvent(e) {
console.log('hello', e);
var anchor = e.target.href;
console.log(anchor);
if (anchor.includes('clientdomain')){
//do nothing
}
else {
SendLinkEvent(anchor);
}
}

You can set custom attributes to the a element like this:
Link A
Then in your js file:
var data_partner= document.getElementById('myAnchor').getAttribute('data-partner');

Related

How to add onclick event to exist element by Javascript? (document.getElementbyID)

I have a button in my project that when you click over it a function call and add onclick event to all certain elements in my project and show my hidden popup element container.
I have a function that search all exist element in my page and add onclick event to some of elements that they have certain class.
My element is stored in a list array. in each cell of this array (array name is list) stored an element like below:
list[0] = document.getElementById("my_div_id");
list[1] = document.getElementById("my_div_id_1");
list[2] = document.getElementById("my_div_id_2");
...
list[n] = document.getElementById("my_div_id_n");
and I have a function like below in top of my Javascript code:
function say_hello(e, msg) {
if (e == null) e = window.event;
//now e handler mouse event in all browser !!!
alert (e + "::" + msg);
}
I have a function to add onclick event to each element in array. I add onclick event in type of below (separated with (*) comment) but doesn't work any of them:
function search_and_add_events_to_all_dragable_elements (list) {
for (var z = 0; z < list.length; z++) {
list[z].href = "javascript:;";
var e;
var test_msg = "VAYYYYYYYYYY";
/**************
element.onclick = new Function { alert ('hi'); };
element.onclick = new Function () { alert ('hi'); };
element.onclick = new function { alert ('hi'); };
element.onclick = new function () { alert ('hi'); };
element.onclick = new function () { return alert ('hi'); };
element.onclick = function () { return alert ('hi'); };
element.onclick = alert ('hi');
element.onclick = "alert ('hi');";
element.onclick = say_hello(e, test_msg);
element.onclick = "say_hello();";
element.onclick = (function (e, test_msg) { return function(e) { sib(e, test_msg); };
element.onclick = (function () { return function() { alert("ahaaay"); };
**************/
list[z].style["padding"] = "20px";
list[z].style["border"] = "solid 10px";
list[z].style["backgroundColor"] = "#CCC";
}
}
I change style in end of my code to perform my code is work and end truly. style change every time but onclick event doesn't add to my div.
only one way add onclick to my project. that is same as below:
list[z].setAttribute("onclick", "alert(\"hi\");");
but are there better ways?
There is a better way. My first mistake was using JavaScript before my all element load on my page. to solve it you must call element in end of page load or put your javascript code in end of your project. then your code execute exactly when your elements are exist in your page.
for more details about it see links below:
JavaScript that executes after page load
http://www.w3schools.com/jsref/event_onload.asp
My second mistake was hurt :(
I has a div that hold all of my other elements in itself. it was styled display: none; on load. when I call my function it was displayed none and all thins work well (like my new styling) but onclick event didn't work :(( and I spent two days to solve this :((
only be careful your element should not be display: none styled when you are adding your onclick event to it.
then you can use this type of creation onclick event dynamically to your project:
list[z].onclick = (function (e, test_msg) {
return function(e) {
sib(e, test_msg);
};
})(e, test_msg);
this is best way that I know. you can manage event handler and send your arguments also to your function.
I use several time another way of dynamically add onclick event in my project.

Google Apps Script Find function caller id

I have a Google Apps Script that dynamically generates buttons and assigns for each a ClickHandler which in turn calls a function.
My problem is that because every button calls the same function I can't find a way to indentify which of them actually made the call. Here is a code sample:
var handler = app.createServerHandler("buttonAction");
for (i=1,...) {
app.createButton(...).setId(i).addClickHandler(handler);
}
function buttonAction() {
//How do I know what button made the call?
}
Another option is to use the e.parameter.source value to determine the ID of the element that triggered the serverHandler to be called.
Here's an example:
function doGet(e) {
var app = UiApp.createApplication();
var handler = app.createServerHandler("buttonAction");
for (var i = 0; i < 4; i++) {
app.add(app.createButton('button'+i).setId(i).addClickHandler(handler));
}
return app;
}
function buttonAction(e) {
var app = UiApp.getActiveApplication();
Logger.log(e.parameter.source);
}
e.parameter.source will contain the ID of the element, which you could then use to call app.getElementById(e.parameter.source) ...
You could create multiple handlers, each for one button:
for (i=1,...) {
var handler = app.createServerHandler("buttonAction" + i);
app.createButton(...).setId(i).addClickHandler(handler);
}
function buttonAction1() {
// code to handle button 1
}
function buttonAction2() {
// code to handle button 2
}
function buttonAction...
I wouldn't recommend of having these sort of "anonymous" action handlers though, as you might be having troubles later in remembering which actionX does what.
(e.g. have a different approach, w/o a loop, or prepare a dictionary-like/array object of meaningful handler names before that loop.)
OTOH, you could use event object argument provided to your callback function:
function buttonAction(event) {
// use event object here to identify where this event came from
}
The thing is the above event object properties depends on where your callback is being called from. For instance, if it were a submit button where you had a Form, then you could access parameters submitted by that from like so: event.parameter.myParamName. See code sample here.
So, if you have a variable number of buttons, you could use a hidden element + the button:
for (i=1,...) {
var hiddenAction = app.createHidden("action", "action"+i);
var handler = app.createServerHandler("buttonAction");
handler.addCallbackElement(hiddenAction);
var btn = app.createButton("Button text", handler);
// you'll need to add both btn and hidden field
// to the UI
app.add(hiddenAction);
app.add(btn);
}
Then, your buttonAction might look like this:
function buttonAction(e) {
var action = e.parameter.action;
// do something based on action value here
// which will be one of "action1", "action2", ...
}
The above is a copy & paste from Hidden class sample.
The above might not work out of the box, but you get the idea: create a hidden element that holds the info you need in your callback, and attach that hidden to your server handler. You could even create multiple hidden elements or a Form panel.
I have the same issue. It works using Tag.
EG
SETUP
var button = addButton(app
,panel
,"buttonActiveTrelloProjects_" + i.toString()
,appVars.buttonWidth() + "px"
,appVars.level2ButtonHeight().toString() + "px"
,false
,false
,"Trello"
,"buttonActiveTrelloProjectsHandler"
,(appVars.buttonLhsGap() * buttonCntr) + (appVars.buttonWidth() * (buttonCntr - 1 ) + 9)
,(appVars.level2ButtonTopGap() * 34)
,3
,"button");
button.setTag(projectName );
USE
function buttonActiveProjectsChartHandler_1(button){
...
buttonTag = getButtonTag(button);
chartType = buttonTag.split(";")[1];
activeProject = buttonTag.split(";")[0];
...
}
function getButtonTag(button){
var jsonButton = JSON.stringify(button);
var source = button.parameter.source;
var tagPtr = source + "_tag";
return button.parameter[tagPtr];
}

Detecting Href Is Clicked

I'm trying to detect if certain element is clicked on onbeforeunload. I can't get it to work. Below is examples of the Javascript code and HTML code on the project (Please note that I have no control over the HTML element as it is not my site)
function checkLeave() {
var p = document.getElementByElementById('yeah');
if (p.href.onclick) {
//do something
}
else {
//do something else
}
}
window.onbeforeunload = checkLeave;
HTML CODE
//The goSomewhere goes to another page
<a id="yeah" href="javascript:goSomewhere();">
<img src="smiley.png">
</a>
Thanks in advance,
J
What you need to do is bind an event handler to each on the page.
This can be done with the following:
// Select all links
//var allLinks = document.querySelectorAll('a[href]');
var allLinks = document.links;
// Bind the event handler to each link individually
for (var i = 0, n = allLinks.length; i < n; i++) {
//allLinks[i].addEventListener('click', function (event) {});
allLinks[i].onclick = function () {
// Do something
};
}
You are testing for the presence of the onclick property to the <a> tag. It isn't present in the markup. Rather than using the onclick, the markup calls a script as the element's href. So you need to look for a script in the href instead:
var p = document.getElementByElementById('yeah');
if (p.href.indexOf("javascript") === 0) {
//do something
}
else {
// do something else
}
Maybe something like this? (just the idea)
document.getElementById('yeah').onclick = function() {
clicked = this.href;
};

setattribute in javascript

This is my code to dynamically set the onclick attribute to links, but without me clicking the links itself, the alert is triggered.
window.onload = function() {
var links = document.getElementsByTagName("a");
for(var i=0;i<links.length;i++) {
elm = links[i];
elm.setAttribute("onclick", alert("you clicked a lik"));
}
}
change the corresponding line to:
elm.setAttribute("onclick", function() { alert("you clicked a link");});
If you pass as argument a function call (such as alert('msg')), the function is executed imediatley and the actual passed argument is the function's return value. All you have to do is wrap your eventHandler code into an anonymous function.
Also, you can declare a function that handles your event and send it's name as argument :
function handleClick() { alert("you clicked a link");}
elm.setAttribute("onclick", handleClick);
P.S. : I recommend using the addEventListener functionality instead of plain old onEvent inline attributes :
elm.addEventListener('click', function() { alert("you clicked a link");}, false);
Try to put the alert statement into an anonimous function
window.onload = function()
{
var links = document.getElementsByTagName("a");
for(var i=0; i < links.length; i++)
{
links[i].setAttribute("onclick", function () {
alert("you clicked a link");
});
}
}

Do something on :target with javascript

I'm using the CSS3 :target pseudo selector to create in-page navigation without reloading the page. This works really well!
But I have a problem, I need to reset the forms in a page when the page targetted, how can I know if an element is targetted with javascript? Like element.ontarget = function();
Or maybe something like element.ondisplaychange -> element.oncsschange?
BETTER UPDATE:
var hashcache = document.location.hash;
window.onhashchange = function() {
if(hashcache != document.location.hash) {
$(hashcache + ' form input').each(function() {
$(this).val('');
});
hashcache = document.location.hash;
}
}
UPDATE:
$('a[href^="#"]').each(function() {
this.onclick = function() {
href = $(this).attr('href');
if(href != document.location.hash) {
$(href + ' form input').each(function() {
$(this).val('');
});
}
}
});
If you're using JavaScript for the navigation, I'd suggest just adding the check to that. But I'm guessing from your question you're not, that you're instead using plain links with just anchors (e.g., <a href='#target1'>, <a href='#target2'>, ...).
A couple of options:
Use a Timer
In that case, basically what you want to do boils down to receiving an event when the anchor changes. As far as I know, and as far as the people answering this other question on StackOverflow in January knew, you can only do that with a timer. (Edit: But see ide's comment below, there's a new hashchange event we'll be able to use soon!) E.g.:
(function() {
var lastHash = window.location.hash;
setTimeout(function() {
var newHash = window.location.hash;
if (newHash !== lastHash) {
lastHash = newHash;
// Trigger your target change stuff
}
}, 250);
})();
That checks for changes every quarter second. That may not be enough for you, you could lower the 250, but beware running too much and slowing everything else down.
But as you say below, this is inefficient.
Hook the Link's click event
Since you're already using JavaScript on the page, I'd recommend using handlers on your links instead. If you add a class name or something to them (I bet they already have one; I'll us "navlink" below), this is easily set up:
var links, index, link;
links = document.getElementsByTagName('a');
for (index = 0; index < links.length; ++index) {
link = links.item(index);
if ((" " + link.className + " ").indexOf(" navlink ") >= 0) {
hookEvent(link, 'click', clickHandler);
}
}
function clickHandler() {
// `this` will reference the element that was clicked
}
// The 'hook' function:
var hookEvent = (function() {
var elm = document.createElement('a');
function hookEventViaAttach(element, event, handler) {
element.attachEvent("on" + event, handler);
}
function hookEventViaAddListener(element, event, handler) {
element.addEventListener(event, handler, false);
}
function hookEventDOM0(element, event, handler) {
element["on" + event.toLowerCase()] = handler;
}
if (elm.attachEvent) {
return hookEventViaAttach;
}
if (elm.addEventListener) {
return hookEventViaAddListener;
}
// I usually throw a failure here saying not supported, but if you want,
// you can use the DOM0-style stuff.
return hookEventDOM0;
})();
A lot of the complication of the above goes away if you use a library like jQuery, Prototype, YUI, Closure, or any of several others.
For instance, the jQuery version:
$("a.navlink").click(clickHandler);
function clickHandler() {
// `this` will reference the element that was clicked
}
The Prototype version:
$$("a.navlink").invoke('observe', 'click', clickHandler);
function clickHandler() {
// `this` will reference the element that was clicked
}
The onfocus property returns the onFocus event handler code on the current element.
event handling code = element.onfocus
The onblur property returns the onBlur event handler code, if any, that exists on the current element.
element.onblur = function;
Example: http://jsfiddle.net/g105b/cGHF7/
<html>
<head>
<title>onblur event example</title>
<script type="text/javascript">
var elem = null;
function initElement()
{
elem = document.getElementById("foo");
// NOTE: doEvent(); or doEvent(param); will NOT work here.
// Must be a reference to a function name, not a function call.
elem.onblur = doEvent;
};
function doEvent()
{
elem.value = 'Bye-Bye';
alert("onblur Event detected!")
}
</script>
<style type="text/css">
<!--
#foo {
border: solid blue 2px;
}
-->
</style>
</head>
<body onload="initElement()";>
<form>
<input type="text" id="foo" value="Hello!" />
</form>
<p>Click on the above element to give it focus, then click outside the
element.<br /> Reload the page from the NavBar.</p>
</body>
</html>
Maybe youcan just code like this
function hashChangeEvent(){
$(window.location.hash)//do something
}
window.onhashchange = hashChangeEvent;//when hash change
hashChangeEvent();//first load

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