Go-to-line on GitHub code page

GH Go-to-line

/*
 * Go to hash location associated with line of code.
 * Assigning line in the if clause is done because parseInt
 * returns falsy if its result is NaN. 
*/ 

function goToLine(line) {
  if (line = parseInt(line)) {
    document.location.hash = "#L" + line;
  }
}

/*
 * Create a text input element. Place it. 
 * Add two keyup listeners: when hitting "Enter",
 * run the goToLine function; second, blur() the input
 * on "Esc" key.
*/

var lineBox = document.createElement("input");
lineBox.setAttribute("style",
             "position: fixed;" +
             "top: 10px;" +
             "right: 10px");
lineBox.setAttribute("type", "text");
document.body.appendChild(lineBox);


lineBox.addEventListener("keyup", function(evt) {
    var key = evt.keyCode || evt.which;

    if (key == 13) {
      goToLine(lineBox.value);
      evt.target.value = "";
      evt.target.blur();
    } else if (key == 27) {
      evt.target.blur();
    }
});

/* 
 * Here is the culprit. Listen for keyup events, and when
 * the key is "/", focus on the input box. Problem: after jumping
 * to a line once, any subsequent attempts populate the input
 * with the "/" character. When listening for keydown, the problem
 * is resolved.
*/

document.addEventListener("keyup", function(evt) {
    var key = evt.keyCode || evt.which;
    if ( key == 191) {
      evt.preventDefault();
      lineBox.focus();
    }
});

Drop this code into the console on a GitHub page. Press "/" to bring focus to the input in the top right. Type in a number, hit Enter and jump to a specific line of code. If you do it again, and if you're using Chrome, you might see that the "/" is placed in the input element.

However, if you change the last eventListener to listen for keydown instead of keyup, you should be able to jump around without having to delete the "/" each time. Strange bug, seems isolated to Chrome.