I have a text field in ASP.NET and i want to allow only alphanumeric and forward slash (/) keys in that. I tried the following code,

```
function jsCheckInput(e) {
    var evt = (e) ? e : window.event;
    var key = (evt.keyCode) ? evt.keyCode : evt.which;
    if (key != null) {
        key = parseInt(key, 10);
        if (key < 47 || (key > 57 && key < 65) || (key > 90 && key < 97) || key > 122) {
            if (!jsIsUserFriendlyChar(key)) {
                return false;
            }
        }
        else {
            if (evt.shiftKey) {
                return true;
            }
        }
    }
    return true;
}

function jsIsUserFriendlyChar(val) {
    // Backspace, Tab, Enter, Insert, and Delete  
    if (val == 8 || val == 9 || val == 13 || val == 45 || val == 46) {
        return true;
    }
    // Ctrl, Alt, CapsLock, Home, End, and Arrows  
    if ((val > 16 && val < 21) || (val > 34 && val < 41)) {
        return true;
    }
    return false;
}

```

In the web forms page i added like below,

```
<asp:TextBox ID="text_value" CssClass="textbox" onkeydown="return jsCheckInput(event);" runat="server"></asp:TextBox>

```

Here i am able to enter alphabets and numbers but i am not able to enter the value `/`. I have enabled the shift key so i can give `shift + ?` to enter the forward slash. Also another problem is when i press shift + any numeric key the special characters there like `! @ # $ % ^ & * ( ) ...` are also coming in tet field. What am i doing wrong here?