<HTML><HEAD>
<!--
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Elementary Validation #3
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-->
<SCRIPT LANGUAGE="JavaScript"><!-- hide from old browsers
/*
THE JAVASCRIPT COOKBOOK by Erica Sadun, webrx@mindspring.com
Copyright (c)2000 by Charles River Media. All Rights Reserved.
This applet can only be re-used or modifed by license holders of the
JavaScript Cookbook CD-ROM. Credit must be given in the source
code and this copyright notice must be maintained. If you do
not hold a license to the JavaScript Cookbook, you may NOT
duplicate or modify this code for your own use.
Use at your own risk. No warranty is given or implied of the suitability
of this applet for any specific application. Neither Erica Sadun nor
Charles River Media will be held responsible for any unwanted effects
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*/
function validate()
{
// Version 3.0 will support
// (typeof(parseInt(document.forms[0].F1.value)) == 'Number')
// for now, we must assume that there is a number there
// or else go through more elaborate parsing
if (document.forms[0].F1.value.length == 0)
{
alert('You must enter a number')
return false
}
// Recover whatever value we can get
var aValue = parseInt(document.forms[0].F1.value)
// Check that it is in range.
if ((aValue < 1) || (aValue > 100))
{
alert('Values must range between 1 and 100')
// prepare field to be overwritten
document.forms[0].F1.focus()
document.forms[0].F1.select()
return false
}
else
return true
}
<!-- done hiding --></SCRIPT></HEAD>
<BODY bgcolor="ffffff" link="0000ff" vlink="770077">
<FONT COLOR="007777"><H1><IMG SRC="../GRAFX/UTENS.JPG" WIDTH=80 HEIGHT=50
ALIGN = LEFT>Validation #3: Number Check</H1></FONT>
<BLOCKQUOTE>
<FONT COLOR="770000">
This script will not submit unless the text field contains a
number ranging between 1 and 100.
</FONT>
<FORM onSubmit='return validate()'>
<INPUT TYPE='TEXT' NAME='F1'>
<INPUT TYPE='SUBMIT'>
</FORM>
</FONT></BLOCKQUOTE>
<FONT COLOR="007777"><H2>Discussion</H2></FONT>
<FONT SIZE=4>
This form's <FONT COLOR="770000">onSubmit</FONT> event
calls the function <FONT COLOR="770000">validate()</FONT>
to check the values in the input field. If the value is
unacceptable, the field is put in focus and the text selected
to prepare for new text input.
</FONT>
<FONT COLOR="770000"><PRE>
function validate()
{
// Version 3.0 will support
// (typeof(parseInt(document.forms[0].F1.value)) == 'Number')
// for now, we must assume that there is a number there
// or else go through more elaborate parsing
if (document.forms[0].F1.value.length == 0)
{
alert('You must enter a number')
return false
}
// Recover whatever value we can get
var aValue = parseInt(document.forms[0].F1.value)
// Check that it is in range.
if ((aValue < 1) || (aValue > 100))
{
alert('Values must range between 1 and 100')
// prepare field to be overwritten
document.forms[0].F1.focus()
document.forms[0].F1.select()
return false
}
else
return true
}
</PRE></FONT>
<h5>Copyright ©1996 by Charles River Media, All Rights Reserved</h5>
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