不确定为什么这不起作用-Javascript基本增量功能

Question

I am writing code to increment the most basic progress bar ever...... it just isn't working. These are the variable used:

map.progress_bar = // the progress div that grows inside a container div that is the width of the screen (100%);

progress = 0;

state.window_width = // the width of the window or otherwise $(window).width();

setTimeout(function incProgress(){
        if ( map.progress_bar.width() < state.window_width ) {
            progress += 10;
            map.progress_bar.css({
                width: String(progress + '%')
            });
            console.log('progress: ', map.progress_bar.width());
            console.log('window: ', state.window_width);
            setTimeout(incProgress(), 300);
        }
    }, 300);

Please do not ask me to do setInterval. Please explain to me why on earth this does not work, I feel very unhappy.

Answer 1

setTimeout(incProgress(), 300);

You are calling the function and passing its return value ( undefined ) to setTimeout .

You need to pass a function to setTimeout .

Remove the () .