Javascript 特殊字符验证

Question

<script language="JavaScript">
var mikExp = /[$\\@\\\#%\^\&\*\(\)\[\]\+\_\{\}\`\~\=\|]/;
function dodacheck(val) 
{
    var strPass = val.value;
    var strLength = strPass.length;
    var lchar = val.value.charAt((strLength) - 1);
    if(lchar.search(mikExp) != -1) 
    {
        var tst = val.value.substring(0, (strLength) - 1);
        val.value = tst;
    }
}
</script>

<input type="text" name="display1" id="display1" value="<?php echo $wc['display1']; ?>" class="width241 input fnt11" onKeyUp="javascript:dodacheck(xyz.display1);" maxlength="20">

此函数确保特殊字符不会打印在输入框中。 但是当我按下 shift 并按下任何特殊字符超过 5 秒时，它会打印特殊字符。

有什么线索可以阻止它发生吗？

Answer 1

试试这个，

var mikExp = /[$\\@\\\#%\^\&\*\(\)\[\]\+\_\{\}\`\~\=\|]/;

    function check(e) {
    var keynum
    var keychar
    var numcheck
    // For Internet Explorer
    if (window.event)
    {
    keynum = e.keyCode
    }
    // For Netscape/Firefox/Opera
    else if (e.which)
    {
    keynum = e.which
    }
    keychar = String.fromCharCode(keynum)
    if ((keychar.toString()).search(mikExp) == 0)
    {

    return false;
    }
    else {
    return true;
    }
    }

    <input type="text" name="display1" id="display1" value="" class="width241 input fnt11" onKeypress="javascript:return check(event);"  maxlength="20">