用JS验证输入框只能输入数值型数据

控件代码：

<asp:TextBox ID="txtDaysOutLB" Text="" MaxLength="4" onkeydown="return jsDecimals(event);" Width="75px" runat="server"></asp:TextBox>

JS代码：

function jsDecimals(e) {
 
    var evt = (e) ? e : window.event;
    var key = (evt.keyCode) ? evt.keyCode : evt.which;
    if (key != null) {
        key = parseInt(key, 10);
        if ((key < 48 || key > 57) && (key < 96 || key > 105)) {
            if (!jsIsUserFriendlyChar(key, "Decimals")) {
                return false;
            }
        }
        else {
            if (evt.shiftKey) {
                return false;
            }
        }
    }
    return true;
}
 
// Function to check for user friendly keys  
//------------------------------------------
function jsIsUserFriendlyChar(val, step) {
    // 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;
    }
    if (step == "Decimals") {
        if (val == 190 || val == 110) {  //Check dot key code should be allowed
            return true;
        }
    }
    // The rest  
    return false;
}.