Question

I want to check the textbox value before postback occurs. I set the onClientClick value to my function but I don’t know how to pass the data to check, in this case I want to check the txt1 entered text.

<asp:textbox id="txt1" runat="server />

<asp:LinkButton ID="LinkButton1"
                runat="server"
                Text="Save" 
                onclick="Save"
                OnClientClick="javascript:check(WANT TO PUT TEXTBOX VALUE HERE);"
                />

My javascript:

function check(txt) {
 var pattern = /^[0-9]{1,11}(,[0-9]{0,2})?$/;
 if (!pattern.test(txt)) {
    return false;
 }
 else {
    return true;
 }
}

The issue is that this check function is used along the keypress event of the txt1 so I cant use:

function check(){
    var txt=$('#txt1').val();
}

The whole JS code:

$('#txt1').keypress(function (e) {
    var key = String.fromCharCode(e.which);
    var txt = $(this).val() + key;
    if (check(txt)) {
        // do sth
    } else {
        e.preventDefault();
        // do sth
    }
});

How can I tell the OnclientCLick function to get the txt1 value?

Thank you.

Answer 1

Something like that :

<asp:textbox id="txt1" runat="server />

<asp:LinkButton ID="LinkButton1"
                runat="server"
                Text="Save" 
                onclick="Save"
                OnClientClick="check(document.getElementById('<%=txt1.ClientID%>').value;)"
                />

---

Edit:
Other methods :

1. You can add it on server side : LinkButton1.OnClientClick="check(document.getElementById('" + txt1.ClientID + "').value;)";

2. If you want to remain in the aspx page, you have to put a name of a javascript function in the OnClientClick and implement the javascript function in a script tag :

   <asp:LinkButton ID="LinkButton1"
                   runat="server"
                   Text="Save" 
                   OnClientClick="validate();"
                   />
   <script type="text/javascript">
       function validate() {
           alert(document.getElementById('<%=txt1.ClientID%>').value);
           return false;
       }
   </script>