Determine if html select contains a value in any of its child options

Given a select

<select id="Mys开发者_C百科elect">
<option value="-1">Please Select<option>
<option value="1">Selection 1<option>
<option value="2">Selection 2<option>
</select>

What the best way to determine if there is an option of value X in the select with JQuery?

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You can do this using a selector and .length, like this:

var exists = $("#mySelect option[value='-1']").length !== 0;

Or as a function:

function optionExists(val) {
  return $("#mySelect option[value='" + val + "']").length !== 0;
}

If it's not numbers and you may have ' in there for example (screwing the selector), you can use .filter(), like this:

function optionExists(val) {
  return $("#mySelect option").filter(function() {
           return this.value === val;
         }).length !== 0;
}

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The :has() selector should work, something like this:

var exists = $("#Myselect:has(option[value='X'])").length > 0;

This is far from the only way, but an easy to understand approach. You could also do somethi.g like this for an .Exists() function since .length > 0 is sometimes not clear to mean it does exist.