Introduction to JavaScript test()
JavaScript test() method is a Regular expression method that matches the expression pattern with the string. RegExp is an in-built object available in JavaScript, providing functionality to match text with patterns. The method test() is of this RegExp object available as RegExp.prototype.test(). The test() method is indeed called upon a RegExp object. It performs a search operation on the specified text using the pattern provided by the RegExp object. The method returns a boolean value, either true or false, indicating whether a match is found. If it founds a game anywhere in the string, it returns true. Otherwise, it returns false.
Syntax:
regexObj.test(str);Parameters
- regex Obj: regexObj is an object of RegExp that defines the regular expression to be searched for.
- str: str is a string where this regular expression will be applied and matched against.
- Return value: returns boolean true or false. True if anyone matches found else faulty.
Example #1
Simple text search
Code:
<!DOCTYPE html>
<html>
<head>
<title>
JavaScript test() Method
</title>
<style>
.body-data {
border : #81D4FA 2px solid;
background-color : #03a9f400;
text-align : left;
padding-left : 20px;
padding-bottom: 20px;
height : auto;
width : auto;
}
.resultText {
margin: 0 0 3px 0;
padding: 0px;
display: block;
font-weight: bold;
}
.heading {
font-weight: bold;
border-bottom: 2px solid #ddd;
font-size: 15px;
width: 98%;
}
.list button[ type = submit] {
background: #2196F3;
padding: 10px 17px 10px 17px;
margin-right: 10px;
color: #fff;
border: none;
}
.list button[ type = submit]:hover {
background: #2173f3;
}
</style>
</head>
<body>
<div class = "body-data">
<div class = "heading">
<h2> JavaScript test() Method </h2>
<p> Click on the test button to execute test() method </p>
</div>
<div class = "list" >
</br>
<label> Pattern: </label>
<p id = "pattern" style = "display: inline-block;" > Default </p>
</br>
<label> Text: </label>
<p id = "text" style = "display: inline-block;" > Default </p>
</br>
<button type = "submit" value = "submit" onclick = "matchPattern()"> test </button>
</div>
<div class = "resultText">
<h3 id = "result1"></h3>
</div>
</div>
<script type = "text/javascript">
var text = "the world is beautiful";
var regex = "is";
document.getElementById("text").innerHTML = text;
document.getElementById("pattern").innerHTML = regex;
function matchPattern() {
var pattern = new RegExp(regex);
var result = pattern.test(text);
document.getElementById("result1").innerHTML = result;
}
</script>
</body>
</html>Output:
Example #2
Using regular expression.
Code:
<!DOCTYPE html>
<html>
<head>
<title>
JavaScript test() Method
</title>
<style>
.body-data {
border : #81D4FA 2px solid;
background-color : #03a9f400;
text-align : left;
padding-left : 20px;
padding-bottom: 20px;
height : auto;
width : auto;
}
.resultText {
margin: 0 0 3px 0;
padding: 0px;
display: block;
font-weight: bold;
}
.heading {
font-weight: bold;
border-bottom: 2px solid #ddd;
font-size: 15px;
width: 98%;
}
.list button[ type = submit] {
background: #2196F3;
padding: 10px 17px 10px 17px;
margin-right: 10px;
color: #fff;
border: none;
}
.list button[ type = submit]:hover {
background: #2173f3;
}
</style>
</head>
<body>
<div class = "body-data">
<div class = "heading">
<h2> JavaScript test() Method </h2>
<p> Click on the test button to execute test() method </p>
</div>
<div class = "list" >
</br>
<label> Text: </label>
<p id = "text" style = "display: inline-block;" > Default </p>
</br>
<button type = "submit" value = "submit" onclick = "matchPattern()"> test </button>
</div>
<div class = "resultText">
<h3 id = "result1"></h3>
<h3 id = "result2"></h3>
</div>
</div>
<script type = "text/javascript">
var text = "the world is beautiful";
var regex = "hel/*";
document.getElementById("text").innerHTML = text;
function matchPattern() {
var pattern = new RegExp(regex);
var result = pattern.test(text);
document.getElementById("result1").innerHTML = "Pattern hel/* : " + result;
var pattern = new RegExp("bea/*");
document.getElementById("result2").innerHTML = "Pattern bea/* : " + pattern.test(text);
}
</script>
</body>
</html>Output:
Example #3
Check if text contains any digit,
Code:
<!DOCTYPE html>
<html>
<head>
<title>
JavaScript test() Method
</title>
<style>
.body-data {
border : #81D4FA 2px solid;
background-color : #03a9f400;
text-align : left;
padding-left : 20px;
padding-bottom: 20px;
height : auto;
width : auto;
}
.resultText {
margin: 0 0 3px 0;
padding: 0px;
display: block;
font-weight: bold;
}
.heading {
font-weight: bold;
border-bottom: 2px solid #ddd;
font-size: 15px;
width: 98%;
}
.form {
margin:5px auto;
max-width: 700px;
padding: 25px 15px 15px 25px;
}
.form li {
margin: 12px 0 0 0;
list-style: none;
}
.form label {
margin: 0 0 3px 0;
padding: 0px;
display: block;
font-weight: bold;
}
.form .field {
width: 80%;
height: 20px;
}
.form button[ type = submit] {
background: #2196F3;
padding: 10px 17px 10px 17px;
margin-right: 10px;
color: #fff;
border: none;
}
.form button[ type = submit]:hover {
background: #2173f3;
}
</style>
</head>
<body>
<div class = "body-data">
<div class = "heading">
<h2> JavaScript test() Method </h2>
<p> Click on the test button to execute test() method </p>
</div>
<form action = "#" onsubmit = "return matchPattern()" >
<ul class = "form" >
<li>
<label> Enter Text <span class = "required" > * </span></label>
<input type="text" class="field" />
</li>
<li>
<button type = "submit" value = "submit"> Validate </button>
</li>
</ul>
</form>
<div class = "resultText">
<h3 id = "result1"></h3>
</div>
</div>
<script type = "text/javascript">
function matchPattern() {
var pattern = new RegExp("[0-9]");
var text = document.getElementsByClassName("field")[0].value;
var result = pattern.test(text);
if(result){
document.getElementById("result1").innerHTML = "Contains Digit" ;
}else {
document.getElementById("result1").innerHTML = "Does not contain any digit" ;
}
}
</script>
</body>
</html>Output:
Advantages
- It’s possible to use regular expressions and implement them directly to search the matches in JavaScript efficiently.
- As the test() method is built-in, there is no need to implement additional logic for searching.
- The code becomes less, and developers can focus more on business logic.
- It’s very simple to use this method.
- As the regular expression is universal, you can take it from any other language and use it in JavaScript.
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