JavaScript method for determining whether a string contains a specified sub-string

JavaScript method for determining whether a string contains a specified sub-string

This article mainly introduces how to use JavaScript to determine whether a string contains a specified sub-string. The example analyzes the javascript string operation skills, which is very useful. For more information, see

 

 

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.

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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.

The 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.