SOURCE

let isComposing = false;
let nativeValue = '';
let input = $('#searchInput');
let n;
var r = "\n  height:0 !important;\n  visibility:hidden !important;\n  overflow:hidden !important;\n  position:absolute !important;\n  z-index:-1000 !important;\n  top:0 !important;\n  right:0 !important\n";
let i = ["letter-spacing", "line-height", "padding-top", "padding-bottom", "font-family", "font-weight", "font-size", "text-rendering", "text-transform", "width", "text-indent", "padding-left", "padding-right", "border-width", "box-sizing"];


input.on('input', function(e) {
  handleInputAction();
  nativeValue = e.target.value;
});

input.on('compositionstart', function() {
  isComposing = true
});

input.on('compositionend', function() {
  // compositionend -> input
  isComposing = false
  handleInputAction();
});

function handleInputAction() {
  if (isComposing) return;
  setTimeout(function() {
    input[0].value = nativeValue;
  });
  
  let style = a(input[0], 1, 3);
  let {minHeight, height} = style;
  input[0].setAttribute('style', `minHeight:${minHeight};height:${height};`);
}

function a(e) {
    var t = arguments.length > 1 && void 0 !== arguments[1] ? arguments[1] : 1
      , A = arguments.length > 2 && void 0 !== arguments[2] ? arguments[2] : null;
    n || (n = document.createElement("textarea"),
    document.body.appendChild(n));
    var i = o(e)
      , a = i.paddingSize
      , s = i.borderSize
      , c = i.boxSizing
      , u = i.contextStyle;
    n.setAttribute("style", "".concat(u, ";").concat(r)),
    n.value = e.value || e.placeholder || "";
    var l = n.scrollHeight
      , d = {};
    "border-box" === c ? l += s : "content-box" === c && (l -= a),
    n.value = "";
    var p = n.scrollHeight - a;
    if (null !== t) {
        var h = p * t;
        "border-box" === c && (h = h + a + s),
        l = Math.max(h, l),
        d.minHeight = "".concat(h, "px")
    }
    if (null !== A) {
        var f = p * A;
        "border-box" === c && (f = f + a + s),
        l = Math.min(f, l)
    }
    return d.height = "".concat(l, "px"),
    n.parentNode && n.parentNode.removeChild(n),
    n = null,
    d
}

function o(e) {
    var t = window.getComputedStyle(e)
      , A = t.getPropertyValue("box-sizing")
      , n = parseFloat(t.getPropertyValue("padding-bottom")) + parseFloat(t.getPropertyValue("padding-top"))
      , r = parseFloat(t.getPropertyValue("border-bottom-width")) + parseFloat(t.getPropertyValue("border-top-width"))
      , o = i.map((function(e) {
        return "".concat(e, ":").concat(t.getPropertyValue(e))
    }
    )).join(";");
    return {
        contextStyle: o,
        paddingSize: n,
        borderSize: r,
        boxSizing: A
    }
}

<div data-v-79343168="" data-v-91fa07c2="" class="search_container searchShow"><div data-v-79343168="" class="search_header"><header data-v-79343168="" class="header_bg"><div data-v-79343168="" class="header_input_bg"><div data-v-2597d6b3="" data-v-79343168="" class="input_wrapper"><div data-v-2597d6b3="" class="back_icon_bg"><img data-v-2597d6b3="" src="//i.thsi.cn/iwencai/wap/img/nav_back_black.png" class="back_icon"></div><div data-v-2597d6b3="" class="input_bg">

<textarea data-v-2597d6b3="" autocomplete="off" id="searchInput" type="search" class="search_input"></textarea>

<div data-v-2597d6b3="" class="clear_input_icon" style=""></div><div data-v-2597d6b3="" class="search_icon_bg"><i data-v-2597d6b3="" class="search_icon"></i></div></div><div data-v-2597d6b3="" class="cancel">搜索</div></div></div></header></div><div data-v-79343168="" class="search_body"><div data-v-79343168="" class="search_content"><!----></div><!----></div></div>