这样更好~!

if (~referrer.toUpperCase().indexOf("RAL")) { 
    console.log("includes")
}

在referrer后添加. touppercase()。此方法将字符串转换为大写字符串。然后，使用. indexof()使用RAL代替RAL。

if (referrer.toUpperCase().indexOf("RAL") === -1) { 

使用正则表达式也可以达到同样的效果(当你想测试动态模式时特别有用):

if (!/Ral/i.test(referrer)) {
   //    ^i = Ignore case flag for RegExp

以下是根据ES6按性能降序排列的选项

包括

if (referrer.toLowerCase().includes("Ral".toLowerCase())) { ... }

IndexOf(这有时会给出类似或更好的结果比Includes)

if (referrer.toLowerCase().indexOf("Ral".toLowerCase()) !== -1) { ... }

匹配

if (referrer.match(new RegExp("Ral", 'i'))) { ... }

基准测试结果:https://jsben.ch/IBbnl

if (referrer.toUpperCase().indexOf("RAL") == -1) { ...

以下是我的看法:

脚本:

var originalText = $("#textContainer").html()
$("#search").on('keyup', function () {
  $("#textContainer").html(originalText)
  var text = $("#textContainer").html()
  var val = $("#search").val()
  if(val=="") return;
  var matches = text.split(val)
  for(var i=0;i<matches.length-1;i++) {
    var ind =  matches[i].indexOf(val)
    var len = val.length
      matches[i] = matches[i] + "<span class='selected'>" + val + "</span>"
  }
  $("#textContainer").html(matches.join(""))

HTML:

<input type="text" id="search">
<div id="textContainer">
lorem ipsum is simply dummy text of the printing and typesetting industry. lorem ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of letraset sheets containing lorem ipsum passages, and more recently with desktop publishing software like Aldus pagemaker including versions of lorem ipsum.</div>

Codepen

任何语言的例子:

'My name is Хведор'.toLocaleLowerCase().includes('ХвЕдОр'.toLocaleLowerCase())