add character to string javascript code example

Example 1: add char in specific index stirng javascript

int j = 123456;
String x = Integer.toString(j);
x = x.substring(0, 4) + "." + x.substring(4, x.length);

//output : 1234.56

Example 2: javascript string concat vs +

It is strongly recommended to use the string
concatenationoperators (+, +=) instead of String.concat
method for perfomance reasons

Example 3: how to add a letter to a string javascript

String.prototype.splice = function(idx, rem, str) {
    return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));
};

var result = "foo baz".splice(4, 0, "bar ");
document.body.innerHTML = result; // "foo bar baz"

Example 4: javascript add to string

var s = 'hell'
s = s + 'o'

Example 5: string concatenation js

var aString="";
aString.concat(value1, value2, ... value_n);