String.match(param) 方法返回一个包含所有匹配项的数组。而 javascript 中的数组没有 .replace 方法 。因此出现错误。您可以尝试类似以下方法：

 a = a.toString().replace(/[\+\-\?]*/g,""); // Array to string converstion

您的匹配返回一个数组，其中没有 replace 。尝试：

a = a[0].replace(/[\+\-\?]*/g , "");

var veri = "+???+Girdiğiniz eposta adresi 'adfadf' geçersiz.-???-";


var a = veri.match(/\+[\?]*\+(.*)*\-[\?]*\-/g);
// The variable 'a' is now an array.
// The first step in debugging is to always make sure you have the values
// you think you have.
console.log(a);

// Arrays have no replace method.
// Perhaps you are trying to access a[0]?
// or did you mean to modify `veri`?
 a = a.replace(/[\+\-\?]*/g , "");
alert(a);