if variable contains
JavascriptVariablesIf StatementJavascript Problem Overview
> Possible Duplicate:
> JavaScript: string contains
I have a postcode variable and want to use JS to add a location into a different variable when the postcode is changed/entered. So for example if ST6 is entered I would want Stoke North to be entered.
I somehow need to do an if statement to run through e.g.
if(code contains ST1)
{
location = stoke central;
}
else if(code contains ST2)
{
location = stoke north;
}
etc...
How would I go about this? It's not checking if 'code' equals a value but if it contains a value, I think this is my problem.
Javascript Solutions
Solution 1 - Javascript
You might want indexOf
if (code.indexOf("ST1") >= 0) { ... }
else if (code.indexOf("ST2") >= 0) { ... }
It checks if contains
is anywhere in the string
variable code
. This requires code
to be a string. If you want this solution to be case-insensitive you have to change the case to all the same with either String.toLowerCase()
or String.toUpperCase()
.
You could also work with a switch
statement like
switch (true) {
case (code.indexOf('ST1') >= 0):
document.write('code contains "ST1"');
break;
case (code.indexOf('ST2') >= 0):
document.write('code contains "ST2"');
break;
case (code.indexOf('ST3') >= 0):
document.write('code contains "ST3"');
break;
}
Solution 2 - Javascript
You can use a regex:
if (/ST1/i.test(code))
Solution 3 - Javascript
The fastest way to check if a string contains another string is using indexOf
:
if (code.indexOf('ST1') !== -1) {
// string code has "ST1" in it
} else {
// string code does not have "ST1" in it
}
Solution 4 - Javascript
if (code.indexOf("ST1")>=0) { location = "stoke central"; }
Solution 5 - Javascript
If you have a lot of these to check you might want to store a list of the mappings and just loop over that, instead of having a bunch of if/else statements. Something like:
var CODE_TO_LOCATION = {
'ST1': 'stoke central',
'ST2': 'stoke north',
// ...
};
function getLocation(text) {
for (var code in CODE_TO_LOCATION) {
if (text.indexOf(code) != -1) {
return CODE_TO_LOCATION[code];
}
}
return null;
}
This way you can easily add more code/location mappings. And if you want to handle more than one location you could just build up an array of locations in the function instead of just returning the first one you find.