javascript-events

问题 Is there a specific event for when a user selects an item in a dropdown box? I am creating a fairly large form that uses multiple dropdown boxes. On load all but the first are disabled, as the user selects the first option the options in the second box change using AJAX and I want to remove the attribute disabled. $('#site_id').on('change', function(event) { $('#access_type_id').removeAttr('disabled'); }); The trouble I am having is that .change() seems to be fired when the options in a

问题 Is there anything that prevents me from adding a event listener to the window that results from a window.open() call? I am trying to set a handler function to be triggered on a visibility change event on the new document, but this handler function is not being called. 回答1: There's nothing that prevents you from doing that ( as long as the window you are opening is in the same domain as the parent/opener window; Just imagine what malicious people could do if that weren't the case ). Once you

问题 Is there anything that prevents me from adding a event listener to the window that results from a window.open() call? I am trying to set a handler function to be triggered on a visibility change event on the new document, but this handler function is not being called. 回答1: There's nothing that prevents you from doing that ( as long as the window you are opening is in the same domain as the parent/opener window; Just imagine what malicious people could do if that weren't the case ). Once you

问题 I have an event, and I want to add additional parameters to the named function. I tried following 2 things: myDiv.addEventListener('click', evt.call(this, event, 'hello')); And myDiv.addEventListener('click', evt(event, 'hello')); And the problem with both of them, is they get called right away, and don't get called when you click myDiv , i.e. when it's supposed to get called. How can I add additional parameters to the named function event? JSFiddle console.clear(); var myDiv = document

问题 I have an event, and I want to add additional parameters to the named function. I tried following 2 things: myDiv.addEventListener('click', evt.call(this, event, 'hello')); And myDiv.addEventListener('click', evt(event, 'hello')); And the problem with both of them, is they get called right away, and don't get called when you click myDiv , i.e. when it's supposed to get called. How can I add additional parameters to the named function event? JSFiddle console.clear(); var myDiv = document

问题 I have an event, and I want to add additional parameters to the named function. I tried following 2 things: myDiv.addEventListener('click', evt.call(this, event, 'hello')); And myDiv.addEventListener('click', evt(event, 'hello')); And the problem with both of them, is they get called right away, and don't get called when you click myDiv , i.e. when it's supposed to get called. How can I add additional parameters to the named function event? JSFiddle console.clear(); var myDiv = document

问题 I have an event, and I want to add additional parameters to the named function. I tried following 2 things: myDiv.addEventListener('click', evt.call(this, event, 'hello')); And myDiv.addEventListener('click', evt(event, 'hello')); And the problem with both of them, is they get called right away, and don't get called when you click myDiv , i.e. when it's supposed to get called. How can I add additional parameters to the named function event? JSFiddle console.clear(); var myDiv = document

问题 I have a parent <div> with one child <div> in memory - not attached to the current document. I want to trigger a CustomEvent on the child but listen to that event from the parent. Here is my code: var parent = document.createElement('div'); var child = document.createElement('div'); parent.appendChild(child); parent.addEventListener('boom', function(event) { console.log('parent listener', event); // <~ This never runs! }); var event = new CustomEvent('boom', { bubbles: true }); child

问题 I have a parent <div> with one child <div> in memory - not attached to the current document. I want to trigger a CustomEvent on the child but listen to that event from the parent. Here is my code: var parent = document.createElement('div'); var child = document.createElement('div'); parent.appendChild(child); parent.addEventListener('boom', function(event) { console.log('parent listener', event); // <~ This never runs! }); var event = new CustomEvent('boom', { bubbles: true }); child

问题 How to change onclick using javascript ? https://jsfiddle.net/749rt0m7/1/ I tried to use this code, but not work. How can i do ? <span onclick="test_fn('aaa,bbb')" id="xx">edit</span> <script> document.getElementById('xx').onclick = "test_fn(111,222)"; </script> 回答1: There are a couple things going on here. First of all test_fn() is not a function in your jsfiddle. You will need to define it in order for it to be called. Second of all you are setting the onclick attribute to be a string not a