enabling button after function returns true

**droidus** · 04-27-2012 02:22 PM

How do I check if a function returns true to enable a button?

Code:

 onkeydown='javascript: $("#usernameDiv").html("Please wait..."); $.get("check.php",{ cmd: "checker", usern: $("#username").val() } ,function(data){  $("#usernameDiv").html(data); });'

this is what I would like to do if the username is available...

Code:

document.getElementById('next').disabled='';

**Padonak** · 04-27-2012 03:59 PM

Code:

var ret = function(){here goes your function which returns true or false};
document.getElementById('next').disabled=(ret == true) ? '' : 'disabled';

**droidus** · 04-27-2012 04:25 PM

doesn't it print out the function?

when i try this, all that shows up in the pop-up is the function code

Code:

var ret = function(){ return false; };
    alert(ret);

in my checkUser.php, i have this:

Code:

if(isset($get['cmd']) && $get['cmd'] == 'check') {

if(!isUserID($user)) {
echo "Invalid User ID";
return false;
//exit();
}

if(empty($username) || strlen($username) < 4) {
echo "Please enter 5 characters or more";
return false;
exit();
}



$rs_duplicate = mysql_query("select count(*) as total from members where username='$username' ") or die();
list($total) = mysql_fetch_row($rs_duplicate);

	if ($total > 0)
	{
		return false;
	//echo "Username not available";
	} else {
		return true;
	//echo "Username available!";
	}
}

so how would i call on this method? i am not entirely sure what one "method" i would call here.

**Padonak** · 04-28-2012 04:03 AM

as for php, i would do it this way:

PHP Code:


$output='';

if(isset($get['cmd']) && $get['cmd'] == 'check'){

if(!isUserID($user)){$output.='Invalid User ID'; echo $output; return;}

if((empty($username)) || (strlen($username) < 4)){$output.='Please enter 5 characters or more'; echo $output; return;}

$rs_duplicate = mysql_query("select count(*) as total from members where username='$username' ") or die();

$num_rows = mysql_num_rows($rs_duplicate);

if($num_rows > 0){$output.='Username not available'; echo $output; return;}

else{$output.='Username available!'; echo $output;}

}

and here is show/hide javascript:

Code:

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>...</title>
<head>
<style type="text/css">
center{padding-top:200px;}
input[type="button"]{margin-left:20px;margin-right:20px;}
#hidden_content{margin:30px;visibility:hidden;}
</style>
</head>
<body>
<center>
<div id="hidden_content"><input type="button" value="My hidden button" /></div>
<input type="button" value="Return true" onclick="x('t')" /><input type="button" value="Return false" onclick="x('f')" />
</center>
<script type="text/javascript">
var ret=function(flag){if(flag=='f'){return false;}if(flag=='t'){return true;}}

function x(flag){/*alert(ret(flag));*/document.getElementById('hidden_content').style.visibility=(ret(flag)==true)?'visible':'hidden';}
</script>
</body>
</html>

**droidus** · 04-28-2012 02:47 PM

so with this php, how would i get a return statement from this?

Code:

$.get("checkUser.php",{ cmd: "check", username: $("#username").val() } ,function(data){  $("#usernameDiv").html(data); });

I would then be able to tie in this from your code:

Code:

var ret=function(flag){if(flag=='f'){return false;}if(flag=='t'){return true;}}
function x(flag){document.getElementById('next2').style.disabled=(ret(flag)==true)?'disabled':'';}

i was just looking at this site: http://api.jquery.com/jQuery.get/

Code:

$.ajax({
  url: url,
  data: data,
  success: success,
  dataType: dataType
});

Would i want to return the method through success, returning either true or false here?

Also, I did several random usernames, and they all return false. Is there something wrong with the code, or is it something else?

**Padonak** · 04-28-2012 04:04 PM

if based on the php-code that i posted above you do not need any true/false checking... just check it right in the $.get callback function like this:

Code:

$.get("checkUser.php",{ cmd: "check", username: $("#username").val() } ,function(data){
$("#usernameDiv").html(data);
// this will enable the button
if(data=='Username available!'){$('#next2').attr('disabled','');}
});

**droidus** · 04-28-2012 08:16 PM

When I enter the username, then the password, it enables the submit button (even though it says "Username not available"). when i do it the other way around, it does not enable it. here is my code:

Code:

<input type="text" name="username" id="username" style="height:40px; font-size:18px;"
    onkeydown='javascript: $("#usernameDiv").html("Please wait..."); 
    $.get
    (
    	"checkUser.php",
    	{ 
        	cmd: "check", username: $("#username").val() 
        },
    	function(data){  
        	$("#usernameDiv").html(data);
			// this will enable the button
			if(data=="Username available!"){ $("#next2").attr("","disabled"); }
        }
    )
    .error(function() { alert("There was an error.  Please try again.  If this persists to happen, please contact us."); });'
    
    onblur='javascript: $("#usernameDiv").html("Please wait..."); 
    $.get
    (
    	"checkUser.php",
    	{ 
        	cmd: "check", username: $("#username").val() 
        },
    	function(data){  
        	$("#usernameDiv").html(data);
			// this will enable the button
			if(data=="Username available!"){ $("#next2").attr("","disabled"); }
        }
    )
    .error(function() { alert("There was an error.  Please try again.  If this persists to happen, please contact us."); });'  />

**Padonak** · 04-29-2012 02:27 AM

what if you try replacing

Code:

$("#next2").attr("","disabled");

in the above code with

Code:

$("#next2").attr("disabled","");

**droidus** · 04-29-2012 10:42 AM

still same issue. here is what I have:

Code:

<input type="text" name="username" id="username" style="height:40px; font-size:18px;"
    onkeydown='javascript: $("#usernameDiv").html("Please wait..."); 
    $.get
    (
    	"checkUser.php",
    	{ 
        	cmd: "check", username: $("#username").val() 
        },
    	function(data){  
        	$("#usernameDiv").html(data);
			// this will enable the button
			if(data=="Username available!"){ $("#nextJava2").attr("disabled",""); }
        }
    )
    .error(function() { alert("There was an error.  Please try again.  If this persists to happen, please contact us."); });'
    
    onblur='javascript: $("#usernameDiv").html("Please wait..."); 
    $.get
    (
    	"checkUser.php",
    	{ 
        	cmd: "check", username: $("#username").val() 
        },
    	function(data){  
        	$("#usernameDiv").html(data);
			// this will enable the button
			if(data=="Username available!"){ $("#nextJava2").attr("disabled",""); }
        }
    )
    .error(function() { alert("There was an error.  Please try again.  If this persists to happen, please contact us."); });'  />

I think another issue is that when checking if the username is available, it always returns "Username not available", even if it really is...

**Padonak** · 04-29-2012 03:14 PM

ok. for some reason(it seems to me i know why but we will not focus on it) this check doesn't work:

Code:

if(data=="Username available!")

but another check works good:

Code:

if(data.indexOf("Username available!")!=-1){$("#next2").removeAttr("disabled");}

here is working example http://ilolo.ru/wd/checkuser/. John, Steve and Mark are already taken by users. it is not a good idea to check the input on key events because it will work for every typed symbol that's why it's assigned on blur in my page.

PHP Code:


<?php

// usernames array (you get it from the DB with SELECT)

$usernames = array('John','Steve','Mark');

$username = $_GET['username'];



$output=''; 

if($_GET['cmd'] == 'check'){

//if(!isUserID($user)){$output.='Invalid User ID'; echo $output; return;}

if((empty($username)) || (strlen($username) < 4)){$output.='<b style="color:Darkorange">Please enter 5 characters or more</b>'; echo $output; return;}

//$rs_duplicate = mysql_query("select count(*) as total from members where username='$username' ") or die();

//$num_rows = mysql_num_rows($rs_duplicate);

//if($num_rows > 0){$output.='Username not available'; echo $output; return;}

if(in_array($username, $usernames)){$output.='<b style="color:Crimson">Username is already taken!</b>'; echo $output; return;}

else{$output.='<b style="color:Green">Username available!</b>'; echo $output;}

}

?>

Code:

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>Enable button</title>
<style type="text/css">
body{text-align:center;font-family:Verdana,Arial;font-size:11px;background-color:#fff;color:#000;}
b{font-size:13px;}
#username{height:40px;font-size:18px;text-align:center;}
</style>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$('#username').focus();
$('#username').blur(function(){
$("#usernameDiv").html("<b>Please wait...</b>");
$.get("checkUser.php",{cmd: "check", username: $("#username").val()},function(data){  
$("#usernameDiv").html(data);
// this will enable the button
if(data.indexOf("Username available!")!=-1){$("#next2").removeAttr('disabled');$("#next2").val('Enabled');}
}
).error(function(){alert("There was an error.  Please try again.  If this persists to happen, please contact us.");});
});
});
</script>
</head>
<body>
<h1>Registration</h1>
<input type="text" name="username" id="username" />
<br /><br />
<div id="usernameDiv">usernameDiv</div>
<br /><br />
<input type="button" id="next2" disabled="disabled" value="Disabled button">
</body>
</html>

**droidus** · 04-29-2012 05:17 PM

I tried a random value (not any of the names in the array), and it still returned "Username not available"

**Padonak** · 04-30-2012 03:39 AM

Originally Posted by droidus

I tried a random value (not any of the names in the array), and it still returned "Username not available"

here are 4 screenshots taken 2 mins ago (Opera, Firefox, Chrome, IE) for username "droidus"

**droidus** · 04-30-2012 11:27 AM

Not sure why it is still not working for me... I am using chrome. here is what i see.

here is my code:
http://pastebin.com/H9pqudu1

**Padonak** · 04-30-2012 12:08 PM

man! the php-part must be in a separate php-file named checkUser.php! take a look at the javascript at $.get("checkUser.php",{cmd: "check", username: $("#username")......

**droidus** · 04-30-2012 12:23 PM

yea; i did have that file. i believe i had two different variable names running around ($username and $user). thanks for your time thought; i appreciate it!

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