imgInp.onchange = evt => { const [file] = imgInp.files if (file) { blah.src = URL.createObjectURL(file) } } <form runat=”server”> <input accept=”image/*” type=”file” id=”imgInp” /> <img id=”blah” src=”#” alt=”your image” /> </form>
To get the path, you can use: var pathname = window.location.pathname; // Returns path only (/path/example.html) var url = window.location.href; // Returns full URL (https://example.com/path/example.html) var origin = window.location.origin; // Returns base URL (https://example.com)
The reason is that one construct: var a = []; // Create a new empty array. a[5] = 5; // Perfectly legal JavaScript that resizes the array. for (var i = 0; i < a.length; i++) { // Iterate over numeric indexes from 0 to 5, as everyone expects. console.log(a[i]); } /* Will display: undefined … Read more
AngularJS remembers the value and compares it to a previous value. This is basic dirty-checking. If there is a change in value, then it fires the change event. The $apply() method, which is what you call when you are transitioning from a non-AngularJS world into an AngularJS world, calls $digest(). A digest is just plain … Read more
Use this: let oldArray = [1, 2, 3, 4, 5]; let newArray = oldArray.slice(); console.log({newArray}); Basically, the slice() operation clones the array and returns a reference to a new array. Also note that: For references, strings and numbers (and not the actual object), slice() copies object references into the new array. Both the original and … Read more
There’s no built-in ability to break in forEach. To interrupt execution you would have to throw an exception of some sort. eg. var BreakException = {}; try { [1, 2, 3].forEach(function(el) { console.log(el); if (el === 2) throw BreakException; }); } catch (e) { if (e !== BreakException) throw e; } JavaScript exceptions aren’t terribly … Read more
Use unshift. It’s like push, except it adds elements to the beginning of the array instead of the end. unshift/push – add an element to the beginning/end of an array shift/pop – remove and return the first/last element of an array A simple diagram… unshift -> [array] <- push shift <- [array] -> pop and … Read more
TL;DR Using the Set constructor and the spread syntax: uniq = […new Set(array)]; “Smart” but naïve way uniqueArray = a.filter(function(item, pos) { return a.indexOf(item) == pos; }) Basically, we iterate over the array and, for each element, check if the first position of this element in the array is equal to the current position. Obviously, … Read more
The correct approach is to use element.getBoundingClientRect(): var rect = element.getBoundingClientRect(); console.log(rect.top, rect.right, rect.bottom, rect.left); Internet Explorer has supported this since as long as you are likely to care about and it was finally standardized in CSSOM Views. All other browsers adopted it a long time ago. Some browsers also return height and width properties, though … Read more
The simplest way would be to use the native Number function: var x = Number(“1000”) If that doesn’t work for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods. parseInt: var x = parseInt(“1000”, 10); // you want to use radix 10 // so you get a decimal number even … Read more