Question

function popup() 
{
    alert (
        "I will tell the truth. I will write deliberately and with accuracy."
        + " I will acknowledge and correct mistakes promptly.  I will preserve"
        + " the original post, using notations to show where I have made changes"
        + " so as to maintain the integrity of my publishing. I will never delete"
        + " a post. I will not delete comments unless they are spam or off-topic."
        + " I will reply to emails and comments when appropriate, and do so promptly."
        + " I will strive for high quality with every post – including basic spellchecking."
        + " I will stay on topic. I will disagree with other opinions respectfully."
        + " I will link to online references and original source materials directly."
        + " I will disclose conflicts of interest. I will keep private issues and topics" 
        + " private, since discussing private issues would jeopardize my personal and work"
        + " relationships.");
} 

Answer 1

You can do only one thing in alert(), add \n which will put the text in newline.

alert ( "I will tell the truth. \n I will write deliberately and with accuracy. \n I will acknowledge and correct mistakes promptly.......")

If you want to apply HTML and styles then go for DHTML box (like lightbox, fancy box…)