The problem with your second part is that, in Internet Explorer 11, the change of the label fires itself a DOMSubtreeModified event, which creates an infinite loop and freezes the browser.
Plus DOMSubtreeModified and similar events are deprecated.
Here's something that works better :
var submitButton = $("#submit button");
submitButton.text("Update");
new MutationObserver(function() {
this.disconnect();
submitButton.text("Update");
this.observe(submitButton[0], {childList: true});
}).observe(submitButton[0], {childList: true});
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