checking form feilds

djdaz

Hi
I have always wondered how to do this but never come accross a way to do it. How do you check to see if certain feilds in a form have been filled out?
Thanks.

kevinsequeira

two ways,
1. use javascript on the form page to check for blank values
2. check on the forms action page for blank values using php
3. use both

example for method1

<script language=javascript>
function check(){
if(document.test_form.f_name.value==''){
alert("cant leave first name blank");
document.test_form.f_name.focus();
return false;
}
document.test_form.submit();
}
</script>

<form name="test_form" method="post" action="test_action.php">
<input type=text name="f_name">
<input type=button name="submit" onClick="javascript:check();" value="submit">
</form>

reg
kevin

djdaz

what about the one in php? i aint really into js.

kevinsequeira

well, its always better to use combination of js and php, cause u dont want the script to go to the action page if nothing is entered and do error checking cause its a waste of the servers resources.

//test.php
<script language=javascript>
function check(){
if(document.test_form.f_name.value==''){
alert("cant leave first name blank");
document.test_form.f_name.focus();
return false;
}
document.test_form.submit();
}
</script>
<form name="test_form" method="post" action="test_action.php">
<input type=text name="f_name">
<input type=button name="submit" onClick="java script:check();" value="submit">
</form>

//test_action.php
<?php
if(isSet($_POST['f_name'])){
	if($_POST['f_name']==""){
		echo "f_name is blank";
		exit;
	}else{
		echo "f_name is ".$_POST['f_name'];
	}
}else{
	echo "f_name is not set";
	exit;
}
?>

reg
kevin

Arc

I used to use only php to field validate and it really is a apain in the but and alot more hassle for the user. PLus you have to deal with info being gone when you use sessions after refreshing the page or going back to a page. So i started using JS to do all field validation and i find it to be more professional looking and easier on the user and me as a programmer.