asp.net textbox javascript function not working/firing?

Question

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my textbox:

ASP

<asp:TextBox ID="TextBox2" runat="server" MaxLength="40" Width="325px" BackColor="LightSalmon" />

javascript:

XML

<script type="text/javascript" language="javascript">
    function checkFilled() {
        var inputVal = document.getElementById("dnn$ctr445$View$TextBox2").value;
        if (inputVal == "") {
            document.getElementById("dnn$ctr445$View$TextBox2").style.backgroundColor = "lightsalmon";
        }
        else {
            document.getElementById("dnn$ctr445$View$TextBox2").style.backgroundColor = "white";
        }
    }
</script>

pageload:

TextBox2.Attributes.Add("onchange", "javascript:checkFilled()")

my textbox is in an updatepanel. what I am trying to accomplish is the textbox back color is light red when empty. When a user types into it, the back color will turn white, and if they delete the textbox text it will turn back to light red. This is just for visual aid and not actually handling any validations.

I don't use a whole lot of javascript so I am not sure if my pageload part is correct.

can anyone give me a hand with why this code isn't working?

Posted 28-Nov-14 6:18am

PTG.Jake

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2 solutions

Solution 2

You could also use keyUp event, this event detects the value entered aswell as the backspace or delete clicked.
Check this fiddle
Fiddle[^]

I posted this answer just as I worked on this and found my option to be different. The answer Sir King has given is absolutely correct and great. I post this with no selfishness, this is just a share.
I hope you understand and look.
Thanks.

Posted 28-Nov-14 7:16am

Suraj Sahoo | Coding Passion

Comments

King Fisher 28-Nov-14 23:23pm

good my 5+ :)

[no name] 29-Nov-14 0:15am

Thank you Sir

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King Fisher · Accepted Answer · 2014-11-28T06:38:00

i hope you looking for this

http://jsfiddle.net/2Xgfr/14/[^]

JavaScript

<script type="text/javascript" language="javascript">
    function checkFilled() {
        var inputVal = document.getElementById('<%= TextBox2.ClientID %>').value;
        if (inputVal == "") {
            document.getElementById('<%= TextBox2.ClientID %>').style.backgroundColor = "lightsalmon";
        }
        else {
            document.getElementById('<%= TextBox2.ClientID %>').style.backgroundColor = "white";
        }
    }
</script>