Checking to see if form input field is empty: javascript, php

Checking to see if form input field is empty

I would like to validate input for a form. I'd like to use either javascript or php to validate the data from several fields. The problem is that for example, one table is called entities. It has 8 records with id's ranging from 1-8. If I hard code it in that this field must be between 1 and 8, then if I add another entity, I then have to go back and recode all of my files. Since I have 12 tables and many fields to check, this could prove to be an administrative nightmare. Is there a way to just say if the field is empty instead of giving it a range?

var entityID = document.myform.entityID.value;
if (! (entityID.length >= 1 && entityID.length <= 8 ))
{
   alert("Please select an entity");
   document.myform.entityID.focus();
   return false;
}

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i found a script online that checks if the field is empty
\
<script language="JavaScript" type="text/javascript">

// Javascript validation functions
// http://www.designplace.org/

//function to check empty fields

function isEmpty(strfield1, strfield2, strfield3) {

//change "field1, field2 and field3" to your field names
strfield1 = document.forms[0].field1.value
strfield2 = document.forms[0].field2.value
strfield3 = document.forms[0].field3.value

//name field
if (strfield1 == "" || strfield1 == null || !isNaN(strfield1) || strfield1.charAt(0) == ' ')
{
alert("\"Field 1\" is a mandatory field.\nPlease amend and retry.")
return false;
}

//url field
if (strfield2 == "" || strfield2 == null || strfield2.charAt(0) == ' ')
{
alert("\"Field 2\" is a mandatory field.\nPlease amend and retry.")
return false;
}

//title field
if (strfield3 == "" || strfield3 == null || strfield3.charAt(0) == ' ')
{
alert("\"Field 3\" is a mandatory field.\nPlease amend and retry.")
return false;
}
return true;
}

//function to check valid email address
function isValidEmail(strEmail){
validRegExp = /^[^@]+@[^@]+.[a-z]{2,}$/i;
strEmail = document.forms[0].email.value;

// search email text for regular exp matches
if (strEmail.search(validRegExp) == -1)
{
alert('A valid e-mail address is required.\nPlease amend and retry');
return false;
}
return true;
}

//function that performs all functions, defined in the onsubmit event handler

function check(form)){
if (isEmpty(form.field1)){
if (isEmpty(form.field2)){
if (isEmpty(form.field3)){
            if (isValidEmail(form.email)){
              return true;
            }
       }
}
}
return false;
}

</script>

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Checking to see if form input field is empty

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javascript, php

PHP Scripting Language

JavaScript

PHP and Databases

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