Use javascript length property to count characters in the given string. This way you will get the number of characters in a string.
Example of JavaScript character count
See below example how you can count the char in string using string.length property:-
<!DOCTYPE html>
<html>
<head>
<title> Example</title>
<script type="text/javascript">
var str = "Hello World!";
var n = str.length;
// show output in alert
alert(n)
</script>
</head>
</html>Output:
TextArea character count JavaScript Example
Using jQuery you can count characters in a textarea. Like how many char can you type inside a TextArea.
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-1.5.js"></script>
<script>
function countChar(val) {
var len = val.value.length;
if (len >= 500) {
val.value = val.value.substring(0, 500);
} else {
$('#charNum').text(500 - len);
}
};
</script>
</head>
<body>
<textarea id="field" onkeyup="countChar(this)"></textarea>
<p>Char Left:</p> <p id="charNum"> </p>
</body>
</html>Output:
Q: How to count occurrences of each character in string javascript?
For example given string is:-
var mainStr = "str1,str2,str3,str4";Find the count of comma , character, which is 3. And the count of individual strings after the split along with a comma, which is 4.
Answer: Use a regular expression
<!DOCTYPE html>
<html>
<head>
<title> Example</title>
<script type="text/javascript">
console.log(("str1,str2,str3,str4".match(/,/g) || []).length); //logs 3
console.log(("str1,str2,str3,str4".match(new RegExp("str", "g")) || []).length); //logs 4
</script>
</head>
</html>Output:
Q: How to Count the frequency of characters in a string using javascript?
For example: “aabsssd”
Output: a:2, b:1, s:3, d:1
I also want to map the same character as a property name in an object.
Answer: Here is code of it:-
<!DOCTYPE html>
<html>
<head>
<title> Example</title>
<script type="text/javascript">
function getFrequency(string) {
var freq = {};
for (var i=0; i<string.length;i++) {
var character = string.charAt(i);
if (freq[character]) {
freq[character]++;
} else {
freq[character] = 1;
}
}
return freq;
};
var out = getFrequency("aabsssd");
console.log(out)
</script>
</head>
</html>Output: Program output in safari console
Do comment if you have any doubts and suggestion on this tutorial.
Note: The All JS Examples codes are tested on the Safari browser (Version 12.0.2) and Chrome.
OS: macOS 10.14 Mojave
Code: HTML 5 Version