<html><body><p>单击该按钮可对“is”后跟“all”不进行区分大小写的全局搜索。</p><button onclick="myFunction()">试一试</button><p id="demo"></p><script>function myFunction() { var str = "Is this all there is"; var patt1 = /is(?! all)/gi; var result = str.match(patt1); document.getElementById("demo").innerHTML = result;}</script></body></html>