var a = "I want apple";
var b = " an";
var position = 6;
var output = [a.slice(0, position), b, a.slice(position)].join('');
console.log(output);
int j = 123456;
String x = Integer.toString(j);
x = x.substring(0, 4) + "." + x.substring(4, x.length);
//output : 1234.56
if (!String.prototype.splice) {
/**
* {JSDoc}
*
* The splice() method changes the content of a string by removing a range of
* characters and/or adding new characters.
*
* @this {String}
* @param {number} start Index at which to start changing the string.
* @param {number} delCount An integer indicating the number of old chars to remove.
* @param {string} newSubStr The String that is spliced in.
* @return {string} A new string with the spliced substring.
*/
String.prototype.splice = function(start, delCount, newSubStr) {
return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
};
}