Using pure javascript, I am trying to create a price-validating function that when used, validates prices entered into a form. There are 4 requirements to my validation:
- Input must be a number and cannot be empty
- If a decimal is entered, there must at least be 1 pre- and post-decimal character
- Price entered must be a number that is between $1 and $99.99 (both inclusive)
- Price entered must not have whitespaces in between
and here is my code:
function formCheck() {
var success = true; //default, assumes client enters all fields correctly so "process.html" will load
var msgBox = document.getElementById('divMessage'); //feedback div
//Price Variables
var movPrice = document.getElementById('txtPrice');
var priceFdBk1 = '<ul><li> Please enter <b>numbers</b> only. </li></ul>';
var priceFdBk2 =
'<ul><li> You entered a decimal point. Please enter a <b>number</b> both before and after the decimal place. </li></ul>';
var priceFdBk3 = '<ul><li> Please enter a movie price between $1.00 to $99.99 (up to 2 decimal places). </li></ul>';
var priceFdBk4 = '<ul><li> Please do not leave a space when entering the movie price. </li></ul>';
//Price Validation
function priceCheck(price, fdBk1, fdBk2, fdBk3, fdBk4) {
//arguments = price and feedbacks if errors are made
var price_clean = price.value.trim(); //price entered by client without whitespace
var price_len = price_clean.length; //number of characters in price entered
//If there is a $ sign, remove it first
var dollarSensor = price_clean.charAt(0);
if (dollarSensor == '$') {
price_clean = price_clean.substring(1);
}
//If there is a decimal point, obtain pre- and post-decimal characters
if (price_clean.indexOf('.') > -1) {
var deciSensor = 1; //remember that input has a decimal
var intValue = price_clean.split('.')[0]; //obtain pre-decimal characters)
var decimalValue = price_clean.split('.')[1]; //obtain post-decimal characters
var postCounter = 0;
for (var j = 0; j < decimalValue.length; j++) {
//count number of decimal places
postCounter += 1;
}
}
//Filter 1: Input must be a number and cannot be empty
if (isNaN(price_clean) || price_clean == '') {
msgBox.innerHTML = fdBk1;
price.className = 'yellow';
success = false;
}
//Filter 2: If a decimal is entered, there must at least be 1 pre- and post-decimal character
else if ((deciSensor == 1 && intValue == '') || (deciSensor == 1 && decimalValue == '')) {
//if client did not enter a number before and after the decimal point
msgBox.innerHTML = fdBk2;
price.className = 'yellow';
success = false;
}
//Filter 3: Price entered must be a number that is between $1 and $99.99 (both inclusive)
else if (price_clean < 1 || price_clean > 99.99 || postCounter > 2) {
msgBox.innerHTML = fdBk3; //message in feedback div
price.className = 'yellow';
success = false; //prevent loading of "process.html" since selected movie is invalid
} else {
price.className = 'transparent';
}
//Filter 4: Price entered must not have whitespaces in between
for (var i = 0; i < price_len; i++) {
oneDigit = price_clean.charAt(i);
if (oneDigit == ' ') {
//if the price float character has a whitespace
msgBox.innerHTML = fdBk4; //message in feedback div
price.className = 'yellow'; //highlight error in client's input
success = false; //prevent loading of "process.html" since selected movie is invalid
} else if (oneDigit == '') {
//if the price float character has no whitespace
price.className = 'transparent'; //remove highlight from client's input
}
}
}
priceCheck(movPrice, priceFdBk1, priceFdBk2, priceFdBk3, priceFdBk4);
return success;
}.yellow {
background-color: yellow;
}
.transparent {
background-color: transparent;
}
h1 {
color: #7157ff;
}
hr {
display: block;
border: 0;
border-top: 3px solid #f90;
padding: 0;
}
textarea {
width: 70%;
}
#div_main {
font-family: Sans-serif;
margin: auto;
margin-top: 30px;
width: 500px;
}
#div_left {
width: 150px;
display: inline-block;
float: left;
}
#div_left p {
margin-bottom: 19px;
}
#div_right {
width: 350px;
display: inline-block;
float: right;
}
.clear {
clear: both;
}<div id="div_main">
<h1>
Add Movie
</h1>
<hr>
<form action="process.html" method="POST">
<div id="div_left">
<p>Price* ($):</p>
</div>
<div id="div_right">
<p><input type="text" id="txtPrice" name="txtPrice"></p>
</div>
<input type="submit" id="btnSubmit" onclick="return formCheck()">
</form>
<div id="divMessage">
*denotes compulsary fields.
</div>
</div>The code works fine but has 1 issue, which I suspect comes from this line:
price_clean = price_clean.substring(1)
Specifically, whenever I enter a "$" sign into the form, my code will remove the "$" sign and validate the input as usual. However, when the input is invalid, it no longer highlights the input box in yellow.
May I know what is going on and how can this be fixed using vanilla javascript? Thank you