1、replace()替换目标字符串，在一个长串中替换子串为另外一个字符串。代码如下：<!DOCTYPE html><html><head><meta charset="utf-8"><title>Test re in js</title></head><body><p>repalce String:"js"</p><p>Where is the js!</p><p id="position"></p><button onclick="myFunction()">Search</button><script>function myFunction() { var str="Where is the js!"; var target="js"; var pattern="baidu"; var pos=str.replace(target,pattern); document.getElementById("position").innerHTML=pos;}</script></body></html>
2、search()寻找目标字符串（target）返回并下标。
3、test()用于测试模式串是否存在于目标字符串中，是返回true，否返回false代码如下：<!DOCTYPE html><html><head><meta charset="utf-8"><title>Test re in js</title></head><body><p>Is :"js" in the text behind.</p><p>Where is the js!</p><p id="position"></p><button onclick="myFunction()">Search</button><script>function myFunction() { var str="Where is the js!"; var pattern=/js/; var result=pattern.test(str); document.getElementById("position").innerHTML=result;}</script></body></html>
4、exec()用于搜索字符匹配返回字符，不存在返回null代码如下：<!DOCTYPE html><html><head><meta charset="utf-8"><title>Test re in js</title></head><body><p>Is :"java" in the text behind.</p><p>Where is the js!</p><p id="position"></p><button onclick="myFunction()">Search</button><script>function myFunction() { var str="Where is the js!"; var pattern=/j/; var result=pattern.exec(str); document.getElementById("position").innerHTML=result;}</script></body></html>
5、如下是正则表达式的参数：
