​x
 
<!DOCTYPE html>
<html>
<body>
​
<p>单击按钮可在字符串中单词的开头或结尾处对“W3”进行全局搜索。</p>
​
<button onclick="myFunction()">试一试</button>
​
<p id="demo"></p>
​
<script>
function myFunction() {
  var str = "Visit W3School"; 
  var patt1 = /\bW3/g;
  var result = str.match(patt1);
  document.getElementById("demo").innerHTML = result;
}
</script>
​
</body>
</html>
​