Sometimes, we need to check which key was pressed or if this key is already pressed before.
This means we have to restrict repeating character.
For example: we want to enter price value in text box.
like
145.26
is valid but
145.26.35
is not
so restrict '.' for single entry
<asp:TextBox ID="Price" runat="server" Text="" onkeypress="javascript:return KeyPriceOnly(event,this);">
function KeyPriceOnly(e, object) {
var KeyID = (window.event) ? event.keyCode : e.which;
if ((KeyID >= 65 && KeyID <= 90) || (KeyID >= 97 && KeyID <= 122) || (KeyID >= 33 && KeyID <= 47 && KeyID != 46) ||
(KeyID >= 58 && KeyID <= 64) || (KeyID >= 91 && KeyID <= 96) || (KeyID >= 123 && KeyID <= 126)) {
return false;
}
if (KeyID == 32) {
return false;
}
if ((KeyID == 46)) {
var strvalue = object.value;
if (strvalue.indexOf(".") > 0)
return false;
}
}