If I put a css property in JS variable, and change the variable value, does the property change?
And a little subquestion: what's difference between let and var, and what should I use?
For example:
let property = document.getElementById("el").style.display;
// variable's content changed
property = "block";
// will the #el's display property change?
let property = document.getElementById("el").style.display;
// variable's content changed
property = "block";
// will the #el's display property change?
No . What is changing is the Javascript variable called property. First of all it takes on the value of the style.display of the element #el and then it is given the value of another string which is 'block'
It is possible to set a property of el but on the 'left hand side' you need to tell JS that is what you want it to do:
document.getElementById("el").style.display = "block";