<input>
const input = document.querySelector("input");

input.addEventListener("paste", (event) => {
  event.stopPropagation();
  event.preventDefault();
  
  const { clipboardData, target } = event;
  
  let pastedText = clipboardData.getData('Text');
  if (pastedText.length == 11 && pastedText.startsWith("8")) {
    pastedText = pastedText.substring(1);
  }
  
  target.value = pastedText;
});

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External JavaScript

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