javascript - 如果数组不包含字符串

Question

我正在制作一个用户注册页面，并且我不想要任何与数组不匹配的字符。

function create(){
var allowed = [
"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z",
"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z",
"1","2","3","4","5","6","7","8","9","0","_","-"];

var username = $("#username").val();

if (username == ""){
document.getElementById("usernameerror").style.color = "red";
document.getElementById("usernameerror").innerHTML = " Username cannot be blank.";
}else{

if (username.indexOf(allowed) != -1){
document.getElementById("usernameerror").style.color = "red";
document.getElementById("usernameerror").innerHTML = " No symbols.";
}else{
document.getElementById("usernameerror").style.color = "blue";
document.getElementById("usernameerror").innerHTML = " ✔";
}

}

}

我敢打赌这很简单..(不是子字符串)

Answer 1

这正是 regular expressions 所遇到的问题。旨在解决。尝试替换这一行:

if (username.indexOf(allowed) != -1){

...这样:

if (!/^[a-z0-9_-]*$/i.test(username)) {

您的要求与 \w metacharacter 非常相似同样，这也可以让您将其用于正则表达式:

/^[\w-]+$/