问在带有JS的字符串中查找最后一个单词字符的索引(例如: /\w/ )

EN

s = "hello world!";
re = /[a-z0-9](?=\W*$)/gi; // global flag is important
re.exec(s);

index = re.lastIndex-1; // 10

function lastCharacterIndex(str){
    var m = str.match(/\w[^\w]*$/);
    return null===m ? -1 : str.lastIndexOf(m[0]);    
}

var s = "hello world!";
var re = /[a-z\d][\W_]*$/i;
var match = re.exec(s);
var index = match ? match.index : -1;
alert(index);  // 10