function ext_mnemoit() {
	var mnemoit = findSelection();
	 location.href='http://www.mnemo.org/index.php?mnemoit='+findSelection();
	}

function findSelection () {
  if (document.getSelection) {
    return document.getSelection();
  } else if (window.getSelection) {
    return window.getSelection();
  } else if (document.selection) {
    return document.selection.createRange().text;
  }
}

document.write('<input type="image" src="http://www.mnemo.org/media/images/mnemoit.002.png" onMouseDown="ext_mnemoit()" />');