Sunday, 22 September 2019

Programming Tricks 1 - PHP and JS/CSS

Programming Tricks 1

PHP

When creating PHP scripts, there is a funny error that if there are spaces before the first <?php tag, the session information is sent before the php script is executed.

So if you get:
 [22-Sep-2019 12:09:17 America/New_York] PHP Warning:  session_start(): Cannot start session when headers already sent in /home/esceqrkk/groundstationdatabase/main.php on line 3
 And there is no code before that main.php file, it's due to the spaces.

Javascript + CSS

A super easy way to animate and control your CSS animations is to use css transitions, css variables and jquery all in one go for example:

JQuery side:
        var currentXTranslation = 0;
        
        $(document).ready(function () {
            $("#NavigateLeftButton").hide();
            
            $("#NavigateLeftButton").click(function(evt) {
     
                currentXTranslation += 100;

                $(':root').css('--current-x-translation', currentXTranslation + "vw"); 
CSS Side:
:root {
        --main-bg-color: #141414;
        --current-x-translation: 0vw;
    }

   
    .Slide {
        margin:auto;
        
        transform: translateX(var(--current-x-translation));
        transition-property: transform;
        transition-duration: 3s;
    }
 
This results in the "Slide" element's transform to be controlled by the JQuery, and the CSS to do the updating.

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