Overview: This code sample provides an inline javascript
source code which can be used to determine a form element
validity: such as numeric or valid email.   Additional parameters
can be passed, indicating whether the field is required and
the maximum length.

(Try it) Cut and Paste (sample)

	

	

	
Email:

	
	

	
Today:

	
	

	
Sku:

	
	

	
Display Order:
 
	
	
	

	
Current Inventory:

	
	

	
Reorder Point:

	
	

	
Description:

	
	

	
Price:

	
	

	

	
	
	

Step 1: Including validation.js

Step 2: Source Code for validation.js

1. Returns the current date in mm/dd/yyyy format

function now() 
{ 
	var stDate; 
	var now; 
	now_date= new Date(); 
	stDate=(now_date.getMonth()+1)+"/"+now_date.getDate()+"/"+now_date.getYear(); 
	return(stDate); 
} 

1. Determines if a string has a valid email structure
2. Functionality from planet-source-code

function IsEmail(sFieldValue)
{
	var checkEmail = "@.";
	var checkStr = sFieldValue;
	var EmailValid = false;
	var EmailAt = false;
	var EmailPeriod = false;

	for (i = 0;  i < checkStr.length;  i++)
	{
		ch = checkStr.charAt(i);
		for (j = 0;  j < checkEmail.length;  j++)
		{
			if (ch == checkEmail.charAt(j) && ch == "@")
				EmailAt = true;
			if (ch == checkEmail.charAt(j) && ch == ".")
				EmailPeriod = true;
			if (EmailAt && EmailPeriod)
				break;
			if (j == checkEmail.length)
				break;
		}
		// if both the @ and . were in the string
		if (EmailAt && EmailPeriod)
		{
			EmailValid = true
			break;
		}
	}

	return(EmailValid);
}

1. Determines if a string is completely numeric
2. Functionality from Planet-Source-Code

function IsNumeric(sFieldValue)
{
	var checkOK = "0123456789";
	var checkStr = sFieldValue;
	var allValid = true;
	var allNum = "";

	if (checkStr=="")
	{
		return(false);
	}
	for (i = 0;  i < checkStr.length;  i++)
	{
		ch = checkStr.charAt(i);

		for (j = 0;  j < checkOK.length;  j++)
		{
			if (ch == checkOK.charAt(j))
				break;
		}
		
		if (j == checkOK.length)
		{
			allValid = false;
			break;
		}

		if (ch != ",")
		{
			allNum += ch;
		}

		if (!allValid)
		{
			allValid =false;
		}
	}

	return(allValid);
}

1. Determine is a field value is numeric or an email
2. Checks if the field is required
3. Checks if the field length has exceeded the maximum size

function FieldValidation(sFieldName, sFieldValue, sRule, bRequired, maxLength)
{
	var sErrorMessage;
	
	sErrorMessage="";

	switch(sRule)
	{
		case "Numeric":
			if (IsNumeric(sFieldValue)==false)
			{
				sErrorMessage+=sFieldName + " is not numeric 
";
			}
			break;
		case "Email":
			if (IsEmail(sFieldValue)==false)
			{
				sErrorMessage+=sFieldName + " is not an email 
";
			}
			break;
	}

	/*------------------------------------------check if field is required---------------------------*/
	if ( (bRequired==true) && (sFieldValue!=""))
	{
		if (sFieldValue.length==0)
		{
			sErrorMessage+=sFieldName + " is required 
";
		}
	}	
	else if ( (bRequired==true) && (sFieldValue==""))
	{
		sErrorMessage+=sFieldName + " is required 
";
	}
	/*------------------------------------check for maxlength--------------------------------------*/
	if ((sFieldValue!="") && (maxLength>0))
	{
		if (sFieldValue.length>maxLength)
		{
			sErrorMessage+=sFieldName + " exceeded the maximum length of " + maxLength + " characters 
";
		}
	}

	return(sErrorMessage);
}

1. Displays the error message in a popup window


function displayErrorMessage(sErrorMsg) 
{
win = window.open(",", 'popup', 'height = 200 width=200 toolbar = yes  titlebar=yes status = no resizeable=yes scrollbars=yes');
win.document.write("Data Validation Errors
");
win.document.write("" + sErrorMsg + "");
}

Attaching javascript code (OnClick)