Determine Whether String Begins With Particular Letters

Question

I am trying to determine using javascript and regex whether a string begins with certain letters. If it's true I want it do something. I am trying to find the value "window_" in a particular string.

My code is as follows:

if (div_type.match(/^\window_/)){

}

This however is returning true when it clearly doesn't contain it.

possible duplicate of [Javascript StartsWith](http://stackoverflow.com/questions/646628/javascript-startswith) — Ja͢ck, Jan 29 '13 at 03:20
@Jack: because it can be `Window`,`window`,`bindow`,`5indow`, etc — vol7ron, Jan 29 '13 at 03:25
@vol7ron Sure, but OP mentioned they want to find value "window_" in a string ... — Ja͢ck, Jan 29 '13 at 03:29
It's not obvious from the question why that condition gives the wrong results. — Ja͢ck, Jan 29 '13 at 03:38

score 3 · Accepted Answer · answered Jan 29 '13 at 03:21

3

Regular expressions are overkill for this kind of string matching:

if (div_type.indexOf("window_") === 0) {
  // Do something
}

answered Jan 29 '13 at 03:21

leepowers

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score 1 · Answer 2 · answered Jan 29 '13 at 03:30

If you really want to go the regex route, you can use test() instead of match() /regex_pattern/.test(string)

Example:

function run(p){
   return /^window_/.test(p);
}

console.log(run("window_boo"),   // true
            run("findow_bar"));  // false

Your use:

if ( /^window_/.test(div_type) ) {
   ...
}

score 0 · Answer 3 · answered Jan 29 '13 at 03:19

0

You don't need a regex for that.

if( div_type.substr(0,"window_".length) == "window_")

answered Jan 29 '13 at 03:19

Niet the Dark Absol

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Determine Whether String Begins With Particular Letters

3 Answers3