ECMAScript 6 String.prototype.startsWith() method can be used to check if a string starts with something. But it is not yet supported by all browsers. Another approach is to use substring.
if (big.substring(0, small.length) == small) {
...
}
Example – case sensitive string starts with check
<script>
var big = "Hello world";
var small = "Hello";
if (big.substring(0, small.length) == small) {
document.write("big string starts with small string");
}
</script>Example – string starts with check ignoring case
<script>
var big = "hello world";
var small = "Hello";
if (big.toLowerCase().substring(0, small.length) == small.toLowerCase()) {
document.write("big string starts with small string (ignoring case)");
}
</script>
