String validation

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widiyantosg

Hi,

I'm a newbie in javascript. I hope somebody will help me.
For example I have 2 textboxes and 1 button. I want to make a validation that if the 2 textboxes is empty when the user click the button then it will show an alert box. How to do that?

here is for the textboxes:
String description = request.getParameter("description");
String quantity = request.getParameter("quantity");

if (description == null || quantity == null){
%>
<script>
alert ('Please enter the necessary information')
history.go(-1);
</script>
<%
}
Wat's wrong with the above code? any sample code? Thanks

javaNoobie

Try validating against empty strings instead of null values

fredmv

That isn't JavaScript, but rather JSP. Moving to the Java forum; you'll get more help over there. Please post in the correct forum next time.

widiyantosg

Still can not.... any ideas?

ray326

Being the MVC Nazi that I am, I'd say your MAIN problem is that you're processing that form with a JSP instead of a servlet.

Javanoobie is right but for tests like that I prefer:

if (description != null && !description.equals("")
     && quantity != null && !quantity.equals("")) { %>
<p>Do HTML for good stuff</p>
<% } else { %>
<p>Do HTML for bad stuff</p>
<% } %>

widiyantosg

Hi, thanks.. but I prefer doing the validation by using javascript since it is faster but I don't know how... any sample code?

<form name="test" method="post" action="request_action1.jsp?action=addrequest">
<input name="description" type="text" size="75">
function validateform()
{
var myForm = document.test;

if (myForm.description.length == 0) 
{
	alert("Please enter the item description");
	history.go(-1);
}

}

but the alert can not be shown... can help me resolve the problem?

javaNoobie

myForm.description.value.length

Note: There are plenty of validation codes if you do a search within the Javascript forum.