JavaScript检查子字符串是否在字符串中的方法

var strnew="Hello Raghu How are u"//Checking existence in entire stringif(strnew.indexOf("Raghu") != -1 ){  alert("Exists");}/*Checking existence at the end of stringFor example, variable result1 in the following example is assigned the value of true because the word "Ishmael" appears at the end of the string. Variable result2 is assigned a value of false because "Raghu" doesn't appear at the end of the string.*/result1 = /Raghu$/.test("Call me Raghu");result2 = /Raghu$/.test("Call me Raghu. Some years ago");/*Checking existence in the begining of stringIn the following example, variable result1 is assigned the value of true because the word "Birds" appears at the beginning of the string. Variable result2 is assigned the value of false because "Birds" doesn't appear at the beginning of the string.*/result1 = /^Birds/.test("Birds fly");result2 = /^Birds/.test("Big Birds fly");