Search the page with Javascript with IE

Question

Good morning!

We are creating a super simple HTML page even for a small document that some users will access. In this document we have a form (input text) of search that will have to return through an "Highlight" what the user searched. It is like the use of CTRL + F even, but through the search field, because the user does not want to search with CTRL + F or even sometimes does not know the command. I searched some JAVASCRIPT on the Internet, found some results. Most work in Chrome, but not in IE 11. As the application needs to be run on IE, because they are not all who own Chrome in the corporation, had to be by IE same.

Code example that worked on Chrome but not on IE:

function doSearch(text) {
    if (window.find && window.getSelection) {
        document.designMode = "on";
        var sel = window.getSelection();
        sel.collapse(document.body, 0);

        while (window.find(text)) {
            document.getElementById("button").blur();
            document.execCommand("HiliteColor", false, "yellow");
            sel.collapseToEnd();
        }
        document.designMode = "off";
    } else if (document.body.createTextRange) {
        var textRange = document.body.createTextRange();
        while (textRange.findText(text)) {
            textRange.execCommand("BackColor", false, "yellow");
            textRange.collapse(false);
        }
    }
}

<input type="text" id="search">
<input type="button" id="button" onmousedown="doSearch(document.getElementById('search').value)" value="Find">

Any idea of a code that works?