gistfile1.js

// get the element we want
var myElement = document.getElementById("myElement");

// get its inner HTML and put it in an array
var myInnerHTML = [myElement.innerHTML];

for(var i = 0; i < 10; i++) {
    // add a string to the end of the myInnerHTML array
    myInnerHTML.push("some value");
}

// join the array
myInnerHTML = myInnerHTML.join("");

// reassign the element's inner html
myElement.innerHTML = myInnerHTML;