Try change you code into this:
function selectTextOnly(containerid) {
var text = document.getElementById(containerid);
if (document.body.createTextRange) {
var range = document.body.createTextRange();
range.moveToElementText(text);
range.select();
} else {
var selection = window.getSelection();
var range = document.createRange();
range.selectNodeContents(text);
selection.removeAllRanges();
selection.addRange(range);
}
}
The if stament is used to check document.body.createTextRange
used only for IE; the else for all other browsers.