- Details
- Written by: Stanko Milosev
- Category: JavaScript
- Hits: 5286
HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<script type="text/javascript" src="/jquery-2.1.4.js"></script>
<script type="text/javascript" src="/index.js" defer></script>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="withoutPromise">
<b>Example without promise:<p/></b>
</div>
<div id="withJqueryPromise">
<b>Example with jQuery promise:<p/></b>
</div>
<div id="pureJavaScriptPromiseWithoutJquery">
<b>Example with pure JavaScript promise (without jQuery):<p/></b>
</div>
</body>
</html>
JS:
/*global console, $, XMLHttpRequest*/
(function () {
"use strict";
function fillResult(id, data) {
$.each(data, function (key, val) {
$(id).append("key: " + key + "<br/>value: " + val + "<p/>");
});
}
function fillPromiseResult(data) {
$.each(JSON.parse(data), function (key, val) {
$('#pureJavaScriptPromiseWithoutJquery').append("key: " + key + "<br/>value: " + val + "<p/>");
});
}
$.getJSON("index.json", function (data) {
fillResult("#withoutPromise", data);
});
$.getJSON("index.json").done(function (data) {
fillResult("#withJqueryPromise", data);
});
function makeRequest() {
return new Promise(function (resolve, reject) {
var myJson = new XMLHttpRequest();
myJson.open("GET", "http://localhost:63342/promiseExample/index.json");
myJson.onload = function () {
if (this.status >= 200 && this.status < 300) {
resolve(myJson.response);
} else {
reject(this.statusText);
}
};
myJson.send();
});
}
makeRequest().then(fillPromiseResult, function (errorMsg) {
$("#pureJavaScriptPromiseWithoutJquery").append(errorMsg);
}).catch(function (err) {
console.log("Error: " + err);
});
}());
JSON:
{
"first": "first test",
"second": "second test",
"nested test": [
{"first nest": "nest one"},
{"second nest": "nest two"}
]
}
Mostly I was using this example. Notice that it seems that resolve method of promise can accept only one parameter, that is why I needed to create function special for promise. Example download from here.
- Details
- Written by: Stanko Milosev
- Category: JavaScript
- Hits: 5247
Example of inline if in javascript:
var a = 30;
var b = 40; v
ar c = ((a < b) ? 2 : 3);
Copy / pasted from here.
Example of inline checking of null:
var whatIWant = someString || "Cookies!";
Copy / pasted from here.
- Details
- Written by: Stanko Milosev
- Category: JavaScript
- Hits: 4902
Idea is to display image as a "brush", which means instead of black (or any other color) line to have image.
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="stylesheet" type="text/css" href="/index.css">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div class="bg sprites sprite_338x338_gc4_ring"></div>
<canvas id="myCanvas" width="338" height="338"></canvas>
</body>
<script>
var myImage = new Image();
myImage.src = "338x338_repeating_gc4_dim_hatch.png";
myImage.onload = function () {
var myCvns = document.getElementById("myCanvas");
var myCntx = myCvns.getContext("2d");
var pat = myCntx.createPattern(myImage, "no-repeat");
myCntx.lineWidth = 10;
//myCntx.strokeStyle = "red";
myCntx.strokeStyle = pat;
myCntx.arc(168, 170, 165, 0, 8, false);
myCntx.stroke();
}
</script>
</html>
Notice line:
myCntx.strokeStyle = pat;
With that we are actually using our pattern to display image. Instead of pat write "red", for example, to see the difference.
Live example:- Details
- Written by: Stanko Milosev
- Category: JavaScript
- Hits: 5032
This morning I was reading this web site, about getters and setters in JavaScript, and here I want to copy / paste code which I saw there:
function wrapValue(_value) {
return {
get value() { return _value; },
set value(newValue) { _value = newValue; }
};
}
var x = wrapValue(5);
console.log(x.value); // output 5
x.value = 7;
console.log(x.value); // output 7