JavaScript to determine whether a string contains a specified sub-string

JavaScript to determine whether a string contains a specified sub-string

This example describes how to use JavaScript to determine whether a string contains a specified sub-string. Share it with you for your reference. The specific analysis is as follows:

The following JS Code defines a contains method for the String object to determine whether the String contains a sub-String, which is very useful.

if (!Array.prototype.indexOf) {  Array.prototype.indexOf = function(obj, start) {     for (var i = (start || 0), j = this.length; i < j; i++) {       if (this[i] === obj) { return i; }     }     return -1;  }}if (!String.prototype.contains) {  String.prototype.contains = function (arg) {    return !!~this.indexOf(arg);  };}

The following is a detailed example, which can be executed in a browser.
Copy codeThe Code is as follows: Enter two strings and check if Strign 1 contains String 2. <br>
String 1: <input id = "foo" type = "text" value = "a quick brown fox jumps over"> <br>
String 2: <input id = "bar" type = "text" value = "fox jumps"> <br>
<Button onclick = "checkstring ()"> Click to check if String 1 contains String 2 </button>
<Script>
If (! Array. prototype. indexOf ){
Array. prototype. indexOf = function (obj, start ){
For (var I = (start | 0), j = this. length; I <j; I ++ ){
If (this [I] === obj) {return I ;}
}
Return-1;
}
}
If (! String. prototype. contains ){
String. prototype. contains = function (arg ){
Return !!~ This. indexOf (arg );
};
}
Function checkstring (){
Var foo = document. getElementById ("foo"). value;
Var bar = document. getElementById ("bar"). value;
Alert (foo. contains (bar ));
}
</Script>

I hope this article will help you design javascript programs.