Here you can find the source of contains(string)
String.prototype.contains = function(string) { return (this.indexOf(string) != -1); }
String.prototype.contains = function(str) { return this.indexOf(str) > -1; }; String.prototype.endsWith = function(suffix) { return this.indexOf(suffix, this.length - suffix.length) !== -1; };
String.prototype.contains = function(str, ignoreCase) { return (ignoreCase ? this.toUpperCase() : this) .indexOf(ignoreCase ? str.toUpperCase() : str) >= 0; }; String.prototype.startsWith = function(str) { return this.indexOf(str) == 0; };
String.prototype.contains = function(str, index) { return (this.indexOf(str, index) !== -1) ? true : false;
String.prototype.contains = function(str,startIndex) { return -1 !== String.prototype.indexOf.call(this,str,startIndex); };
String.prototype.contains = function(strPattern){ if(typeof strPattern !== 'string') return false; var pattern = new RegExp(strPattern, "i"); return pattern.test(this); console.log("teste".contains("teste"));
String.prototype.contains = function(string) { return this.indexOf(string) > -1; };
String.prototype.contains = function (string, index) { return this.indexOf(string, index) !== -1; };
String.prototype.contains = function (string, index) { return this.indexOf(string, index) !== -1; };
String.prototype.contains = function(stringSet) { for (var i=0;i<stringSet.length;i++) { if (this.indexOf(stringSet[i]) >= 0) return true; return false; };