js代码

<script>
var inputField = document.querySelector(".demo__input-img")

function pickSample(img) {
  updateImages(img.src)
  inputField.value = img.getAttribute("src")
}

function updateImages(src) {
  var imgs = document.querySelectorAll(".demo__item img")
  for (var i = 0; i < imgs.length; i++) imgs[i].src = src
}

document.addEventListener("click", function(event) {
  if (/demo__option-img/.test(event.target.className)) pickSample(event.target)
}, false)

inputField.addEventListener("input", function() {
  updateImages(this.value)
}, false)

inputField.addEventListener("focus", function() {
  this.select()
}, false)

pickSample(document.querySelector(".demo__option-img"))
</script>