To concatenate multiple string variables, use the JavaScript concatenation operator.
Example
You can try to run the following code to concatenate variables
Live Demo
<html>
<body>
<script>
var str1 = "Tutorials ";
var str2 = "Point: ";
var str3 = "Simply Easy Learning"
var res = str1 + str2 + str3;
document.write("String 1 = "+str1);
document.write("<br>String 2 = "+str2);
document.write("<br>String 3 = "+str3);
document.write("<br>After concatenaton: "+res);
</script>
</body>
</html>