Alex Rivera | Logout

Check if string begins with something?

Asked 2009-11-19T23:12:31.963
292

I know that I can do like ^= to see if an id starts with something, and I tried using that for this, but it didn't work. Basically, I'm retrieving a URL and I want to set a class for an element for path names that start in a certain way.

Example:

var pathname = window.location.pathname;  //gives me /sub/1/train/yonks/459087

I want to make sure that for every path that starts with /sub/1, I can set a class for an element:

if (pathname ^= '/sub/1') {  //this didn't work... 
        ...
javascript string match
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1 Answer

26

First, lets extend the string object. Thanks to Ricardo Peres for the prototype, I think using the variable 'string' works better than 'needle' in the context of making it more readable.

String.prototype.beginsWith = function (string) {
    return(this.indexOf(string) === 0);
};

Then you use it like this. Caution! Makes the code extremely readable.

var pathname = window.location.pathname;
if (pathname.beginsWith('/sub/1')) {
    // Do stuff here
}
answered 2012-05-18T03:30:25.077

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