Question

我正在制作一个用户注册页面，我不希望任何与该数组不匹配的字符。

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 = " ✔";
}

}

}

我敢打赌它很简单......（不是子字符串）

Answer 1

这正是regular expressions旨在解决的问题。尝试替换此行：

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

......用这个：

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

您的要求也与\w metacharacter非常相似，这样您就可以将其用于正则表达式：

/^[\w-]+$/

Answer 2

怎么样：

＆＃13;

if (username.match(/[^\w-]/) !== null) {
  console.log('username has non-word characters...');
}

＆＃13;

请参阅此处了解\ w的作用：MDN Regular Expression。

Answer 3

检查出来：

if (/^[a-z0-9\-\_]+$/.test(username)) {
  document.getElementById("usernameerror").style.color = "red";
  document.getElementById("usernameerror").innerHTML = " No symbols.";
}else{
  document.getElementById("usernameerror").style.color = "blue";
  document.getElementById("usernameerror").innerHTML = " ✔";
}

如果数组不包含字符串

3 个答案: