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一，效果图。
二，代码。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript 正则表达式</title>
</head>
<body>
<!--search方法使用正则表达式-->
<p>搜索字符串"w3cSchool",并显示匹配的起始位置</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
var str = "Visit W3cSchool!";
var n = str.search(/w3cSchool/i);
document.getElementById("demo").innerHTML = n;
}
</script>
<!--search方法使用字符串-->
<p>搜索字符串 "W3cSchool", 并显示匹配的起始位置：</p>
<button onclick="myFunction()">点我</button>
<p id="demo1"></p>
<script>
function myFunction() {
var str = "Visit W3cSchool!";
var n = str.search("W3cSchool");
document.getElementById("demo1").innerHTML = n;
}
</script>
<!--replace方法使用正则表达式-->
<p>替换"microsoft"为"w3cschool</p>
<button onclick="myFunction()">点我</button>
<p id="demo3">Please visit microsoft</p>
<script>
function myFunction() {
var str = document.getElementById("demo3").innerHTML;
var txt = str.replace(/microsoft/i, "w3cshool");
document.getElementById("demo3").innerHTML = txt;
}
</script>
<!--replace方法使用字符串-->
<p>替换"microsoft"为"w3cschool"</p>
<button onclick="myFunction()">点我</button>
<p id="demo4">please visit microsoft</p>
<script>
function myFunction() {
var str = document.getElementById("demo4").innerHTML;
var txt = str.replace(/microsoft/i, "w3cschool");
document.getElementById("demo4").innerHTML = txt;
}
</script>
<!--使用 test()-->
<script>
var patt1 = new RegExp("e");
document.write(patt1.test("The best things in life are free"));
</script>
<!--使用 exec()-->
<script>
var patt1 = new RegExp("e");
document.write(patt1.exec("the best things in life are free"));
</script>
</body>
</html>
参考资料：《菜鸟教程》