how to insert textbox values by selecting from radiobutton list in asp.net into sql

/ Only allows numeric values
function isNumeric(num){
    var charCode = (num.which) ? num.which : event.keyCode;
    if (charCode > 31 && (charCode < 48 || charCode > 57)) { return false; }
    else { return true; }
}

// Validates TextBox Length
function validateTextBoxLength() {
    var tb = document.getElementById("TextBox1").value;
    if (tb.length > 1 && tb.length != 4) {
        alert("TextBox must be 4 digits.");
        return false;
    }
    return true;
}

// Check for RadioButtonList selection
function rbSelectedValue() {
    var radio = document.getElementsByName('<%= rblSearchType.ClientID %>');
    var tb = document.getElementById("TextBox1").value;
    for (var i = 0; i < radio.length; i++) {
        if (radio[i].checked) {
            // alert("RadioButton 1 Selected");
            if (tb.length > 1 && tb.length != 4) {
                alert("TextBox must be 4 digits.");
                return false;
            }
            else {
            return true;
            }
        }
        else {
        // alert("RadioButton 2 Selected");
        return true;
    }
}