如何验证文本框中的特殊字符并在错误消息中显示输入的特殊字符?

你可以这样做:

var invalidChars = str.match(/[^\w ]/g), output = '';
if (invalidChars) {
    invalidChars = invalidChars.unique();
    var lastInvalidChar = invalidChars.pop();
    output = 'You have used the illegal character' + (invalidChars.length > 0 ? 's' : '') + ' ' +
        invalidChars.join(', ') + (invalidChars.length > 0 ? ' and ' : '') + lastInvalidChar;
}

在这里 match /[^\w ]/g 用于获取既不是单词字符也不是空格的所有字符。然后使用自定义的 unique

因为JavaScript没有内置的

Array.prototype.unique = function() {
    var index = {};
    for (var i=0; i<this.length; ++i) {
        if (!index.hasOwnProperty(this[i])) {
            index[this[i]] = this[i];
        }
    }
    var clean = [];
    for (var prop in index) {
        if (index.hasOwnProperty(prop)) {
            clean.push(index[prop]);
        }
    }
    return clean;
};

请注意,此实现不是类型安全的,因为这些值用作属性名,因此被转换为字符串。所以呢 ["3",3].unique() 退货 ["3"] 因此 "3".toString() === (3).toString() .

var myString = document.getElementById("myInputField").value; // gets the sentence
var invalidChars = myString.replace(/[^#%\^]*/g, ""); //gets the chars | "#%^" in your case
var response = "";

for(var  i = 0; i < invalidChars.length; i+){
  response += (i > 0? (i == invalidChars-1 ? " and ": ", "):"") + invalidChars[i];
}

if (response != "") {
  alert("Your data contains invalid characters " + response);
}

http://www.regular-expressions.info/javascript.html