Mastering The Faster Web with PHP, MySQL, and JavaScript

Caching DOM values

When accessing an object repeatedly, it is much more efficient to store it in a local variable in order to use it over and over again. For example, the following code makes a local copy of the grouped DOM values instead of accessing each value separately:

function myJS(){    let group = document.getElementById("grouped");    group.property1 = "value1";    group.property2 = "value2";    group.property3 = "value3";    group.property4 = "value4";        // Instead of:    //    // document.getElementById("grouped").property1 = "value1";    // document.getElementById("grouped").property2 = "value2";    // document.getElementById("grouped").property3 = "value3";    // document.getElementById("grouped").property4 = "value4";        }

Doing so will allow you to avoid the ...