My Monkey Do

A Log of Coding Solutions

javascript

Javascript Date parsing UTC or Local?

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When parsing a string in a javascript Date object, if you don’t set a time, the string is taken in as UTC. Then when retrieving it, it displays as local time.

new Date('2020-01-01');

will return “Tue Dec 31 2019 14:00:00 GMT-1000 (Hawaii-Aleutian Standard Time) {}” when the current time is after 10am HST.

However,

new Date('2020-01-01 00:00:00');

will return “Wed Jan 01 2020 00:00:00 GMT-1000 (Hawaii-Aleutian Standard Time) {}” anytime, even after 10am HST.

Obviously, this is due to timezones. This stack overflow gets into the nitty gritty details:

https://stackoverflow.com/questions/5619202/converting-a-string-to-a-date-in-javascript

Javascript Done Resize

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Normally code in the resize event is meant to just run once when the user is done resizing.  This code below, from css-tricks and seen elsewhere will do the trick:


var resizeTimer;
$(window).on('resize', function(e) {
clearTimeout(resizeTimer);
resizeTimer = setTimeout(function() {
// Run code here, resizing has "stopped"
}, 250);
});

Escape strings for use in JavaScript

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When using parameters from the URL, it should always be sanitized before using it in your javascript.

Using jQuery you can easily do:

var safeString = $(“<span></span>”).text(unsafeString).html();

Using plain javascript:

var entityMap = {
    "&": "&amp;",
    "<": "&lt;",
    ">": "&gt;",
    '"': '&quot;',
    "'": '&#39;',
    "/": '&#x2F;'
  };

  function escapeHtml(string) {
    return String(string).replace(/[&<>"'\/]/g, function (s) {
      return entityMap[s];
    });
  }

The stackoverflow discussion can be found here:  http://stackoverflow.com/questions/24816/escaping-html-strings-with-jquery

 

iPad textarea not selectable

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Problem

The textarea on iPad could not be selected and could not have anything entered.

Solution

The textarea in iPad only responds to the ‘touchstart’ event and not the ‘click’ event, but regular input accepts the ‘click’ apparently.  I some javascript where it would catch the ‘touchstart’ event and trigger a ‘click’ event to make things a little faster on iPads.  This prevented the textarea from being selected and edited.

Another possible solution was I didn’t have the cols and rows attribute in the textarea html tag.  Adding these attributes before the class or id attributes solved it for some people.

http://stackoverflow.com/questions/3909843/why-is-my-text-area-disabled-on-ipad