Home/ Questions/Q 6859901
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-27T02:20:29+00:00

I can’t seem to define a for loop function, what am I doing wrong?

  • 0

I can’t seem to define a for loop function, what am I doing wrong?

My HTML code:

<body onload="generate()">

My Javascript code:

function generate(){
    for(i = 0; i < 150; i++) {
        document.write("<div></div>");
    }
};
Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Your loop is fine (other than that you don’t declare i, and so you fall prey to the Horror of Implicit Globals), it’s document.write that’s the problem. You can only use document.write in an inline script, not after the page has been loaded (e.g., not in the body load event). If you use document.write after the page is loaded, it tears down the page and replaces it with what you output (because there’s an implicit document.open call). So in your case, your page disappears and 150 blank divs are there instead.

    To manipulate the page after load, you’ll want to use the DOM, references:

    For instance, here’s how you’d write your generate function to append 150 blank divs to the page:

    function generate() {
    var i;

    for (i = 0; i < 150; i++){
        document.body.appendChild(document.createElement('div'));
    }
}

    Or more usefully, 150 divs with their numbers in:

    function generate() {
    var i, div;

    for (i = 0; i < 150; i++){
        div = document.createElement('div');
        div.innerHTML = "I'm div #" + i;
        document.body.appendChild(div);
    }
}

    Live copy

    Separately, if you’re going to do any significant DOM manipulation, it’s well worth using a good JavaScript browser library like jQuery, Prototype, YUI, Closure, or any of several others. These smooth over browser differences (and outright bugs), provide useful utility functions, and generally let you concentrate on what you’re actually trying to do rather than fiddling about with inconsistencies between IE and Chrome, Opera and Safari…

    • 0