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What is the difference between typeof and instanceof and when should one be used vs. the other?
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A good reason to use typeof is if the variable may be undefined.
alert(typeof undefinedVariable); // alerts the string "undefined"
alert(undefinedVariable instanceof Object); // throws an exception
A good reason to use instanceof is if the variable may be null.
var myNullVar = null;
ale...
How to change theme for AlertDialog
...was wondering if someone could help me out. I am trying to create a custom AlertDialog. In order to do this, I added the following line of code in styles.xml
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Android Notification Sound
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USE Can Codeding
String en_alert, th_alert, en_title, th_title, id;
int noti_all, noti_1, noti_2, noti_3, noti_4 = 0, Langage;
class method
Intent intent = new Intent(context, ReserveStatusActivity.class);
PendingIntent pendingIntent = PendingInte...
Using HTML5/Canvas/JavaScript to take in-browser screenshots
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JavaScript can read the DOM and render a fairly accurate representation of that using canvas. I have been working on a script which converts HTML into a canvas image. Decided today to make an implementation of it into sending fee...
Get value from hidden field using jQuery
...t type="hidden" value="" id='h_v' class='h_v'> Using jQuery I want to alert the user to this value .
7 Answers
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Detecting arrow key presses in JavaScript
...down = function(e) {
switch (e.keyCode) {
case 37:
alert('left');
break;
case 38:
alert('up');
break;
case 39:
alert('right');
break;
case 40:
alert('down');
break;
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Find JavaScript function definition in Chrome
...e thing they don't seem to have (that I could find) is a way to find a JavaScript function's definition. This would be super handy for me because I'm working on a site that includes many external JS files. Sure grep solves this but in the browser would be much better. I mean, the browser has to know...
Handling optional parameters in javascript
... = props.id || 1;
props.callback = props.callback || function(){};
alert( props.callback )
};
getData( {
id: 3,
callback: function(){ alert('hi'); }
} );
Benefits:
you don't have to account for argument order
you don't have to do type checking
it's easier to define default valu...
How can I upload files asynchronously?
...ick:
$(':button').on('click', function () {
$.ajax({
// Your server script to process the upload
url: 'upload.php',
type: 'POST',
// Form data
data: new FormData($('form')[0]),
// Tell jQuery not to process data or worry about content-type
// You *must* include these...
Detect Click into Iframe using JavaScript
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The above script is used by me to detect clicks away from my site. Most advertising networks now serve banners in frames. If you click one and then quickly another one before you left on the first click, technically I want to know the ...