not able to validate text box using java script

Question

my input text box source like this:

<asp:TextBox ID="TxtDepCode" runat="server" Height="18px"></asp:TextBox>

and my javascript function like this:

  <script type="text/javascript" language="javascript">
    function confirm_user() {
        var userPass = document.getElementById('TxtDepCode');
        alert(userPass)
        if (userPass=''){
        alert("value is blank")
        }
        if (confirm("Department already available, would you like to update ?") == true)
            return true;
        else
            return false;
    }
</script>

in submit button click i want to check wethar corresponding text is empty or not my submit button click event like this:

Akshey Bhat · Accepted Answer · 2016-06-05T12:22:06.810

1

var userPass = document.getElementById('TxtDepCode').value;

Or

var userPass = document.getElementById('<%=TxtDepCode.ClientID%>').value;

Modify the first line of function to get value of textbox as above

if (userPass==''){

Modify if as above

edited Jun 05 '16 at 12:22

answered Jun 05 '16 at 12:10

Akshey Bhat

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Modify your if statement also as given in modified answer – Akshey Bhat Jun 05 '16 at 12:15
var userPass = document.getElementById('TxtDepCode').value; alert(userPass) – user3262364 Jun 05 '16 at 12:17
i am just cheking wethar i am getting my input value in that variable..but not getting – user3262364 Jun 05 '16 at 12:18
now got it sir.if you dont mind y i want to add clientID – user3262364 Jun 05 '16 at 12:23
No need if you got it. You need to use client id in case textbox is nested in some other control. – Akshey Bhat Jun 05 '16 at 12:24
@user3262364 Make sure you return false if user is blank – Moussa Khalil Jun 05 '16 at 12:28

score 1 · Answer 2 · edited May 23 '17 at 12:08

The crucial issues in the code are as follows:

Get the value of the password and not the element:

var userPass = document.getElementById('TxtDepCode').value;
Change the if to == or === instead of single =

if (userPass == '') {
You are using <asp:TextBox> that can have a dynamic ID. Therefore you should get the dynamic ID using .NET's ClientID:

var userPass = document.getElementById('<% =TxtDepCode.ClientID %>').value;

score 0 · Answer 3 · answered Jun 05 '16 at 12:13

You need to return false if value is blank too

<script type="text/javascript" language="javascript">
function confirm_user() {
    var userPass = document.getElementById('TxtDepCode');
    alert(userPass)
    if (userPass.value == ''){ // == not = and userPass.value
    alert("value is blank");
    return false; // Need to stop the function
    }
    if (confirm("Department already available, would you like to update ?") == true)
        return true;
    else
        return false;
}

not able to validate text box using java script

3 Answers3