Looking for certain strings within a field

**pcbrainbuster** · 02-26-2007, 05:58 PM

Hello all

,

I have seen on the web certain fields that for example ask for your email and if it does not include a certain string/number... then it is not sent.

All i know that indexOf is used for this but i do not know how to use it

Can anyone help me with my problem???

**CrazyCoder** · 02-26-2007, 06:04 PM

Code:

  var string = "some string";
  
   if(string.indexOf("some") > -1)
       alert("string found");

**pcbrainbuster** · 02-26-2007, 06:09 PM

Thanks for your post

But there are only two things i do not understand how to set it to search 2 or more values/strings and what is that part > -1 does that say if the value/string(s) are there then do the following ?

Please explain these area and go deep into > -1 Thanks

**CrazyCoder** · 02-26-2007, 06:13 PM

-1 is returned when the script cannot find the index of the string asked for so im checking if my value returned is higher then -1

if you want to dig deeper and find more solutions to finding strings.

visit the following site http://www.javascriptkit.com/javatutors/string4.shtml

**pcbrainbuster** · 02-26-2007, 06:22 PM

Well now i am going try a few/couply tests to see if i get the whole thing

**pcbrainbuster** · 02-26-2007, 06:35 PM

Hello again

,

I tried a test and failed please tell me what went wrong -

<html>
<body>
<input type="text" id="text1"><input type="button" onclick="asd()" value="Send">
<script>
var a = document.getElementById('text1').value
function asd() {
if (a.indexOf("q") > -1) {
alert("Sent\!\!\!")}
else {alert("Sorry Invalid Entry")}
}
</script>
</body>
</html>

Thanks

**CrazyCoder** · 02-27-2007, 02:13 AM

its because your code is wrong.
try the following

Code:

<html>
<head>
<script type="text/javascript" language="JavaScript">
function asd() {
//you got the control ok but not getting the value when the user clicked this is correct
var a = document.getElementById('text1').value
if (a.indexOf("q") > -1) {
//no clue why you were escaping your !
alert("Sent ! ! !")}
else {alert("Sorry Invalid Entry")}
}
</script>
</head>
<body>
<input type="text" id="text1"><input type="button" onclick="asd()" value="Send">
</body>
</html>

**pcbrainbuster** · 02-27-2007, 07:32 AM

Well there is a problem your script, works correctly but most sites say the the variables should always be put before the function but in our scrpts that is the only difference mine is above your is under...

Please explain about thus

Thanks

**Blake** · 02-27-2007, 12:51 PM

In your version, the variable a is assigned the value of the field text1 when the page loads (nothing). You need to assign to a the value of the field text1 when the button is clicked, not when the page loads.

There's nothing wrong with declaring the variable inside the function. It will just be local to the function then. If you want a to be a global variable (I don't see any reason to), you would need to do something like this:

Code:

<html>
<head>
<script type="text/javascript" language="JavaScript">
var a;

function asd()
{
  a = document.getElementById('text1').value;
  if (a.indexOf("q") > -1) alert("Sent ! ! !");
  else alert("Sorry Invalid Entry");
}
</script>
</head>
<body>
<input type="text" id="text1"><input type="button" onclick="asd()" value="Send">
</body>
</html>

**CrazyCoder** · 02-27-2007, 03:32 PM

Thank you for clearing this up Black

pcbrainbuster I think you should propably read a book on javascript not saying it's bad to jump in and try but get a basic idea of how things work.

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