I want to call the function "details" when an element with the class "link" is clicked. This code doesn't work:
window.onload = function () {
document.getElementById("link").onclick = details;
}
How can I do this?
document.getElementById("link") will select an element with an id of "link", not an element with a class of "link".
Depending on what browsers you need to support, you might use document.getElementsByClassName() instead. (Won't work in IE8 or below, but works in all other browsers you are likely to care about.) You'll have to assign the click handler to each element that is returned.
Related
I'm currently implementing a classical Minesweeper game in Vue.js which is working fine so far https://github.com/franktopel/defuse, Demo http://connexo.de/defuse/.
Now I would like to add touch support because as of now, to mark a field as "contains a mine" it is required that you right-click the field. Right-clicking is obviously not available on touch devices, so I would like to add longtap support. I'm using native events click and click.right from the parent component for each field, so the field does not handle the events, but the parent component that instantiates these fields does.
I've found this https://github.com/jerrybendy/vue-touch-events and added it to my project, yet it seems I cannot use this on the component tag (see https://github.com/franktopel/defuse/blob/master/src/components/Defuse.vue):
<m-field
v-for="field in row"
:field="field"
:key="`${field.x},${field.y}`"
#click.native="open(field)"
#click.right.native.prevent="toggleBombMarker(field)"
v-touch:longtap="toggleBombMarker(field)"
></m-field>
because that marks all fields without any user interaction and the console keeps producing
You may have an infinite update loop in a component render function.
This is how my field objects (which I'm passing to the field component) are created:
let Field = function (x, y) {
this.x = x
this.y = y
this.isOpen = false
this.hasBomb = false
this.isMarked = false
this.numNeighbourBombs = null
}
module.exports = Field
I have also tried emitting a custom event from inside my field component, yet I don't know how I can pass the triggering field to the event handler from there.
Can anyone push me in the right direction?
According to the vue-touch-events docs, the v-touch directive doesn't work in the same way as v-on; v-touch must be given a function to execute, whereas the toggleBombMarker(field) expression probably returns undefined.
If you want to pass extra parameters to the v-touch handler, your handler must return a function like this:
methods: {
toggleBombMarker(field) {
return () => {
// your handler code here
}
}
}
How does one code to use an external js function for onclick handler in a button in an dialog with the ability to pass values from dijit.Dialog elements or must it be coded entirely inline?
I'm not entirely sure about what you're trying to say, but if you really want to call an external function, but you have no idea how to pass the parameters, you can still write an inline click handler that passes the arguments to your external function, for example:
registry.byId("myBtn").on("click", function() {
var param1 = myDialog.get("param");
externalFunction(param1);
});
Here is the example:
http://jsfiddle.net/hulufei/twr4thuh/7/
It just worked when bind onClick in virtual dom(like line 18), but If I comment line 18 and comment off line 8 to bind click with addEventListener, it failed.
So what's the problem?
TestUtils triggers events within react's synthetic event system, so the native event that addEventListener listens for is never going to be triggered. You will need to use the native click method on the element in your test:
var events = Events();
ReactTestUtils.renderIntoDocument(events);
events.refs.button.getDOMNode().click();
events.state.event.should.equal('click');
Additionally, you've misspelled clickHandler in your addEventListener definition.
jsfiddle
You can also simplify adding your event listener by reusing your prop definition:
componentDidMount: function () {
this.refs.button.getDOMNode().addEventListener('click', this.clickHandler);
},
Note:
Is there a reason why you want to use addEventListener instead of just passing an onClick attribute for your button? Unless there's a specific and good reason otherwise, i'd suggest doing things the react way when handling events for sanity :)
Edit
I originally mentioned that I did not know what TestUtils' SimulateNative.click did not trigger the event. I was wrong in thinking that it ever would since it would be simulating a native click event within the react even system. #thilo pointed me in the right direction :)
I had many problems while testing addEventListener, and I got the following conclusion.
You can create the events listener with pure javascript, jquery, but when running the tests with Jest I always had a problem.
The rendering of ReactTestUtils does not work directly with the document, and when we do:
For example, our events were added in the document, when rendering with ReactTestUtils it creates a div and renders it in the div, This way I could not get Simulate to trigger the call.
My first solution was to use jquery to create the listener and to test I did the render manually by appending the div in document.body, and triggered the events with the dispachEvent of javascript. But I thought the code was dirty, not the best way to work.
I made a sample code by adding the event and testing it with Jest, also have a test teaching to get all the listener that were created.
You can find the code here: https://github.com/LVCarnevalli/create-react-app/tree/master/src/components/datepicker
Component:
componentDidMount() {
ReactDOM.findDOMNode(this.datePicker.refs.input).addEventListener("change", (event) => {
const value = event.target.value;
this.handleChange(Moment(value).toISOString(), value);
});
}
Test:
it('change empty value date picker', () => {
const app = ReactTestUtils.renderIntoDocument(<Datepicker />);
const datePicker = ReactDOM.findDOMNode(app.datePicker.refs.input);
const value = "";
const event = new Event("change");
datePicker.value = value;
datePicker.dispatchEvent(event);
expect(app.state.formattedValue).toEqual(value);
});
Links:
window.addEventListener not triggered by simulated events: https://github.com/airbnb/enzyme/issues/426
Creating and triggering events: https://developer.mozilla.org/en-US/docs/Web/Guide/Events/Creating_and_triggering_events
What is equivalent of jquery $.off(event) to remove event on element by passing event name in Dojo?
I tried :
dojo.disconnect(handle) // but I dont have an handle to event
How to get the handle or is there any better way to to it?
There is no out of the box solution as far as I know of, so you would have to implement one by yourself. However, this could be a dangerous feature, if you suddenly disconnect all event handlers of a specific type.
However, you could use the dojo/aspect module to intercept calls to the dojo/on module, for example:
aspect.around(arguments, 0, function(original) {
on.signals = [ ];
return function(dom, name, handler) {
console.log(arguments);
on.signals.push({
signal: original.apply(this, arguments),
name: name
});
};
}, true);
I didn't find a proper way to put an aspect around a function itself, rather than a function wrapped inside an object. So I used a dirty trick and used the arguments array and because the on module is my first argument, this will put an aspect around the dojo/on reference.
What happens is that when you bind an event handler using dojo/on, it will save it inside an array. Now you could write your own dojo/on::off() function, for example:
on.off = function(eventName) {
arrayUtils.forEach(on.signals, function(signal) {
if (signal.name === eventName) {
signal.signal.remove();
}
});
};
Now you can use:
on.off("click");
To disconnect all click event handlers.
A full example can be found on JSFiddle: http://jsfiddle.net/Lj5yG/ but this could probably be improved.
I have a regular anchor tag with href attribute set to "#". Normally, this prevents from any navigation but in durandal it navigates me to the home view. How can I stop it from navigating to that view?
I can't change the html and stylings. It needs to be that anchor tag. But I can bind a click event to it. Is there any way to cancel navigation in anchor click event?
regards
Bind a click event to it and call event.preventDefault()
Example
$(function() {
$('#someAnchor').click(function(event) { event.preventDefault(); });
});
This will prevent the browser from propagating the click event and nothing will happen. But inside the click event you can do whatever logic you want.
If you are using knockout to bind the click event then please refer to this stackoverflow post on how to do it from a knockout binding.
EDIT ** Per Tyrsius' comments its a better practice to use the knockout binding to bind a click event.
So, instead it is recommended you do:
ClickMe
clickhandler = function (e) {
e.cancelBubble = true;
if (e.stopPropagation) e.stopPropagation();
};
Have all your anchor links start with a prefix. Then have in your router.guardRoute function this:
if (_.startsWith(instruction.fragment, YOUR_PREFIX))
return false;
}
Worked well for me and no need to add anything else to your app views.
PS. _.startsWith is lodash function. If not using lodash do JS string indexOf or whatever