Form Validation - Prevent submit if fields are blank

Cepeleon · #1 (**permalink**) 03-15-05, 06:47 AM

Hi,

I need to validate a form when the user hits submit.

Basically I want to say that if certain fields on the form have a value of " " then display a message box and prevent the form being submitted to the ASP file ELSE submit the form normally.

Now I came up with something but its not working because when I hit submit with the fields blank its being sent to the process.asp file with not message box appearing.

What is wrong with what I am doing?

In the header I put this,

Code:

function checkIt(f)
{   
if (f.elements['Field1name'].value=="" && f.elements['Field2name'].value=="")   
{      
alert('You have not specified the products you wish to order please go back to step 2');
     return false;   
}   
return true;
}

In the body I put this,

Code:

<form method="post" action="process.asp" name="sForm" onSubmit="return checkIt(this);">
...

Any ideas?

tusamni · #2 (**permalink**) 03-15-05, 03:51 PM

I am also looking for a solution to a similar problem...

Consider this a free bump..

-Erik

djwayne_2004 · #3 (**permalink**) 03-15-05, 04:33 PM

Hi,

To fix your problem change your form tag value to:

Code:

<form method="post" action="process.asp" name="sform" onSubmit="return checkForm(this); return false;">

And change your javascript to:

Code:

function checkForm(f)
{
    if (f.elements['FieldName1'].value == "" && f.elements['FieldName2'].value == "")
    {
        alert("You have not specified the products you wish to order please go back to step 2");
        return false;
    }
    else
    {
        f.submit();
        return false;
    }
}

This should now stop the form from being submitted unless both fields have something in them. Hope this helps.

Wayne

anees220 · #4 (**permalink**) 02-14-13, 12:04 PM

Try this

Code:

<html>
	<head>
		<script type="text/javascript">
			function formValidation(){
				var selectForm = document.myForm; // Selecting Form
				var formLength = selectForm.elements.length; // getting total no. of elements in it
				for(var x=0; x<=formLength; x++){
					var usingLoop = selectForm.elements[x]; // 
					if(usingLoop.value == 0){ // Checking throug Loop
						return false;
					}
				}
			}
		</script>
	</head>
	<body>
		<form action="<?php $_SERVER['PHP_SELF'];?>" name='myForm' method='POST'>
			<input type="text" name='t1'/>
			<input type="text" name='t2'/>
			<input type="text" name='t3'/>
			<input type="submit" onclick='formValidation();'/>
		</form>
	</body>
</html>

kunalanand82 · #5 (**permalink**) 02-15-13, 10:02 PM

You should use "or" operator (||) at the place of "and" operator(&&). When you are using "and" operator then that means alert will be shown only if both the condition matches( if both text fields will be left empty) otherwise it will return true and asp page will be displayed. On the other hand if you are using "or" operator alert will be shown even if one of the field will be left empty(and also when both of the field will be left empty).
Your Expression will go like:
if (f.elements['Field1name'].value=="" || f.elements['Field2name'].value=="")
in place of:
if (f.elements['Field1name'].value=="" && f.elements['Field2name'].value=="")

kunalanand82 · #6 (**permalink**) 02-15-13, 10:06 PM

Use "OR" Operator(||) at the pace of "AND"(&&)
Use expression:
if (f.elements['Field1name'].value=="" || f.elements['Field2name'].value=="")
in place of:
if (f.elements['Field1name'].value=="" && f.elements['Field2name'].value=="")