PHP注意：未定义的索引：在第30行的C：\ xampp \ htdocs \ try1.php中执行
问题描述：
I am currently learning php for fun. When i was googling aorund, i found this code and wanted to try it. When i typed it, this error came out. I want to know why this error happens and how can i fix it. Thank you in advanced.
Notice: Undefined index: step in C:\xampp\htdocs\try1.php on line 30
<?php
/*
Description: Body Mass Index Calculator
Author: Murray Moffatt for A Web 4 U Designs
Notes: Originally written for use on CarolynGibson.com
History:
2003-04-?? : Initial coding.
2005-02-13 : Remove extra CarolynGibson.com HTML and make
stand-alone for publishing on WeberDev.com.
2005-02-16 : Get $step variable from $_POST and add a
"Go Back" option at the end.
*/
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Body Mass Index</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="author" content="A Web 4 U Designs - www.aweb4u.co.nz">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<h3>Body Mass Index (BMI)</h3>
<?php
$step = $_POST["step"];
if ($step == "") {
?>
<p>The Body Mass Index (BMI) is a formula used to estimate the proportion
of your body that consists of fat. It is currently the best guide for
calculating a healthy weight range for people aged between 20 and 65.</p>
<p>Do you want to work in metric (centimetres and kilograms) or imperial
(inches and pounds)?</p>
<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post" name="unitsForm" id="unitsForm">
<table border="0" cellspacing="1" cellpadding="2">
<tr>
<td align="left"><input name="units" type="radio" value="metric" checked>
Metric</td>
</tr>
<tr>
<td align="left"><input type="radio" name="units" value="imperial">
Imperial</td>
</tr>
<tr>
<td><input type="submit" name="Submit" value="Next ->">
<input name="step" type="hidden" id="step" value="1">
</td>
</tr>
</table>
</form>
<?php
}
if ($step == "1") {
$units = $_POST["units"];
?>
<p>Type your weight and height measurements into the boxes below:</p>
<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post" name="inputForm" id="inputForm">
<table border="0" cellspacing="1" cellpadding="2">
<tr>
<td align="right"><b>Your weight:</b></td>
<td align="left"><input name="weight" type="text" id="weight" size="6" maxlength="6">
<?php if ($units == "metric") echo " kilos"; else echo "pounds"; ?>
</td>
</tr>
<tr>
<td align="right"><b>Your height:</b></td>
<td align="left"><input name="height" type="text" id="height" size="6" maxlength="6">
<?php if ($units == "metric") echo " cm (i.e. 177 is 1.77 meters)"; else echo " inches (i.e. 67 is 5 feet 7 inches)"; ?>
</td>
</tr>
<tr>
<td><input name="step" type="hidden" id="step" value="2">
<input name="units" type="hidden" id="units" value="<?php echo $units; ?>">
</td>
<td><input type="submit" name="Submit" value="Next ->">
</td>
</tr>
</table>
</form>
<?php
}
if ($step == "2") {
$units = $_POST["units"];
$weight = $_POST["weight"];
$height = $_POST["height"];
if (!IsValidNumber($weight, ".", 2, 1, 999)) {
echo "<p>The weight measurement you entered, \"$weight\", is invalid.<br>";
echo "Please enter a number between 1 and 999, optionally with up to two decimal places.<br>";
echo "For example <b>90.5</b> is 90 and a half, <b>105.25</b> is 105 and a quarter.</p>";
echo "<p>Please press Back on your browser and try again.</p>";
die("</body></html>");
}
if (!IsValidNumber($height, ".", 2, 1, 999)) {
echo "<p>The height measurement you entered, \"$height\", is invalid.<br>";
echo "Please enter a number between 1 and 999, optionally with up to two decimal places.<br>";
echo "For example <b>90.5</b> is 90 and a half, <b>105.25</b> is 105 and a quarter.</p>";
echo "<p>Please press Back on your browser and try again.</p>";
die("</body></html>");
}
if ($units == "metric") {
$height = $height / 100; // Convert from centimeters to meters
$bmi = round($weight / ($height * $height), 1);
$height = $height * 100; // Convert back to centimeters
} else {
$heightcm = ($height * 2.54) / 100; // Convert from inches to meters
$weightkilo = $weight * 0.4536; // Convert from pounds to kilos
$bmi = round($weightkilo / ($heightcm * $heightcm), 1);
}
?>
<p>According to your height of <?php echo $height; ?>
<?php if ($units == "metric") echo "cm"; else echo "inches"; ?>
and weight of <?php echo $weight; ?>
<?php if ($units == "metric") echo "kilograms"; else echo "pounds"; ?>
your Body Mass Index is <b><?php echo $bmi; ?></b>.</p>
<p>The answer that you get with this equation is NOT your weight but is
the factor that is used to establish your healthy weight range.</p>
<p>A Body Mass Index of <?php echo $bmi; ?> indicates that
<?php
if ($bmi < 20) {
echo " you are underweight.";
}
if ($bmi >= 20 and $bmi <= 24.9) {
echo " your weight is within the ideal range.";
}
if ($bmi >= 25 and $bmi <= 26.9) {
echo " you are slightly overweight.";
}
if ($bmi > 27) {
echo " you are overweight and at risk of weight-related problems.";
}
?>
</p>
<p><a href="<?php echo $_SERVER["PHP_SELF"];?>">Go Back</a><p>
<?php
}
function IsValidNumber($number, $decimal = null, $dec_prec = null, $min = null, $max = null) {
if (is_array($number)) {
extract($number);
}
$dec_prec = $dec_prec ? "{1,$dec_prec}" : '+';
$dec_regex = $decimal ? "[$decimal][0-9]$dec_prec" : '';
if (!preg_match("|^[-+]?\s*[0-9]+($dec_regex)?\$|", $number)) {
return false;
}
if ($decimal != '.') {
$number = strtr($number, $decimal, '.');
}
$number = (float)$number;
if ($min !== null && $min > $number) {
return false;
}
if ($max !== null && $max < $number) {
return false; `enter code here`
}
return true;
}
?>
</body>
</html>
答
You have to check if the post is having that index.
$step = $_POST["step"];
to
if(isset($_POST["step"]){
$step = $_POST['step'];
} else {
$step = "";
}
One liner for above
$step = isset($_POST["step"]) ? $_POST['step'] : "";
Make sure you change in all places where ever you are using the post directly.
答
I don't know why it occurs, but you can hide this notice using
error_reporting(0);
int the starting of your php file.
I've passed 0 in the parameter, since i don't want any error or notice to see in the webpage.