It seems that pseudo-elements are readonly? I am trying to do
window.getComputedStyle(this.inputTextElement, "::ms-clear").setProperty("display", "none");
but I get exception NoModificationAllowedError
.
The closest working thing to set this in JavaScript seems to be doing
var style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = '::-ms-clear{display:none};';
document.getElementsByTagName('head')[0].appendChild(style);