如何使用javascript阻止或限制輸入字段中的特殊字符

Question

Yazi&nbsp;<input type="text" id="yazi" value="">
<button onclick="ElaveEt();">OK</button>

<div id="list"></div>
<script>
    function ElaveEt() {
        if (document.getElementById("yazi").value.c.length > null) {
            objYazi = document.getElementById("yazi");
            objList = document.getElementById("list");

            objList.innerHTML = objList.innerHTML  + '<div id="Step">'+ objYazi.value + '<button  onclick="YaziniSil();" >Sil</button>' + '<div>';
            //document.getElementById("list").innerHTML = document.getElementById("list").innerHTML + '<br>' + document.getElementById("yazi").value;
            document.getElementById("yazi").value = null;

        } else {
            alert('Boş xana əlavə oluna bilməz!')
        }
    }
    function YaziniSil() {
        document.getElementById("Step").remove();
    }
</script>

Answer 1

如果您只想對輸入內容授權字母數字，這是我的建議：

<input type="text" id="yazi" value=""  onkeypress="return alpha(event)"/>
    <button onclick="ElaveEt();">OK</button>

    <div id="list"></div>
    </div>
        <script>
            function ElaveEt() {
                if (document.getElementById("yazi").value.length > 0) {
                    objYazi = document.getElementById("yazi");
                    objList = document.getElementById("list");

                    objList.innerHTML = objList.innerHTML  + '<div id="Step">'+ objYazi.value + '<button  onclick="YaziniSil();" >Sil</button>' + '<div>';
                    //document.getElementById("list").innerHTML = document.getElementById("list").innerHTML + '<br>' + document.getElementById("yazi").value;
                    document.getElementById("yazi").value = null;

                } else {
                    alert('Boş xana əlavə oluna bilməz!')
                }
            }
            function YaziniSil() {
                document.getElementById("Step").remove();
            }

         function alpha(e) {
            var k;
            document.all ? k = e.keyCode : k = e.which;
            return ((k > 64 && k < 91) || (k > 96 && k < 123) || k == 8 || k == 32 || (k >= 48 && k <= 57));
        }
        </script>