Form Validation :
EXAMPLE








Click here to see a sample page using this script.




THE ENTIRE SCRIPT
If you want to use all four validation scripts and the script that will check all fields at once, feel free to copy the entire code listed below to your page.

Note:
The function called formvalidation() needs to be customized to fit your own form.


<script>

function emailvalidation(entered, alertbox)
{
// E-mail Validation by Henrik Petersen / NetKontoret
// Explained at www.echoecho.com/jsforms.htm
// Please do not remove this line and the two lines above.
with (entered)
{
apos=value.indexOf("@");
dotpos=value.lastIndexOf(".");
lastpos=value.length-1;
if (apos<1 || dotpos-apos<2 || lastpos-dotpos>3 || lastpos-dotpos<2)
{if (alertbox) {alert(alertbox);} return false;}
else {return true;}
}
}

function valuevalidation(entered, min, max, alertbox, datatype)
{
// Value Validation by Henrik Petersen / NetKontoret
// Explained at www.echoecho.com/jsforms.htm
// Please do not remove this line and the two lines above.
with (entered)
{
checkvalue=parseFloat(value);
if (datatype)
{smalldatatype=datatype.toLowerCase();
if (smalldatatype.charAt(0)=="i") {checkvalue=parseInt(value)};
}
if ((parseFloat(min)==min && checkvalue<min) || (parseFloat(max)==max && checkvalue>max) || value!=checkvalue)
{if (alertbox!="") {alert(alertbox);} return false;}
else {return true;}
}
}


function digitvalidation(entered, min, max, alertbox, datatype)
{
// Digit Validation by Henrik Petersen / NetKontoret
// Explained at www.echoecho.com/jsforms.htm
// Please do not remove this line and the two lines above.
with (entered)
{
checkvalue=parseFloat(value);
if (datatype)
{smalldatatype=datatype.toLowerCase();
if (smalldatatype.charAt(0)=="i")
{checkvalue=parseInt(value); if (value.indexOf(".")!=-1) {checkvalue=checkvalue+1}};
}
if ((parseFloat(min)==min && value.length<min) || (parseFloat(max)==max && value.length>max) || value!=checkvalue)
{if (alertbox!="") {alert(alertbox);} return false;}
else {return true;}
}
}


function emptyvalidation(entered, alertbox)
{
// Emptyfield Validation by Henrik Petersen / NetKontoret
// Explained at www.echoecho.com/jsforms.htm
// Please do not remove this line and the two lines above.
with (entered)
{
if (value==null || value=="")
{if (alertbox!="") {alert(alertbox);} return false;}
else {return true;}
}
}


function formvalidation(thisform)
{
// This function checks the entire form before it is submitted
// Note: This function needs to be customized to fit your form
with (thisform)
{
if (emailvalidation(Email,"Illegal E-mail")==false) {Email.focus(); return false;};
if (valuevalidation(Value,0,5,"Value MUST be in the range 0-5")==false) {Value.focus(); return false;};
if (digitvalidation(Digits,3,4,"You MUST enter 3 or 4 integer digits","I")==false) {Digits.focus(); return false;};
if (emptyvalidation(Whatever,"The textfield is empty")==false) {Whatever.focus(); return false;};
}
}
</script>



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