显示错误消息与警报框使用JavaScript

Question

i want to display error message without alert box by using javascript.

i have tried with code.

function validatetextbox() {
var txtuname = document.getElementById('<%=txt_uname.ClientID %>').value;
if(txtuname=="") {
    document.getElementById("text_uname").innerHTML= "Enter Username"; } }

but it is not working, please give some suggestions

Answer 1

You need to use document.getElementById('<%=txt_uname.ClientID %>') instead of document.getElementById("text_uname")

Complete function

function validatetextbox() {
    var txtuname = document.getElementById('<%=txt_uname.ClientID %>').value;
    if (txtuname == "") {
        document.getElementById('<%=txt_uname.ClientID %>').innerHTML = "Enter Username";
    }
}

Answer 2

try to cache dom, and set innerHTML

function validatetextbox() {

    var inputEl = document.getElementById('<%=txt_uname.ClientID %>'),
       txtuname = inputEl.value;

    if ( txtuname == "" ) {
        inputEl.innerHTML = "Enter Username";
    }
}

Answer 3

It seems like you need to show alert in txt_uname .. then you should do like this:

function test(){
    var txtuname =document.getElementById('<%=txt_uname.ClientID %>').value;

     if(txtuname == "") {
       document.getElementById('<%=txt_uname.ClientID %>').value= "Enter Username";
         } 
    }

Answer 4

try this

function test()
{ 
var row = lnk.parentNode.parentNode;
var txtuname= row.cells[your cell number].childNodes[your node number].innerHTML;
if(txtuname=="")
{
txtuname="enter username";
}

}