select <select> item by value

If you are using jQuery (1.6 or greater)

$('#x option[value="5"]').prop('selected', true)

If someone looking for jquery solution, use the val() function.

$("#select").val(valueToBeSelected);

In Javascript,

document.getElementById("select").value = valueToBeSelected; 

Using Javascript:

document.getElementById('drpSelectSourceLibrary').value = 'Seven';

If you can, with ES6...

function setOption(selectElement, value) {
    return [...selectElement.options].some((option, index) => {
        if (option.value == value) {
            selectElement.selectedIndex = index;
            return true;
        }
    });
}

...otherwise...

function setOption(selectElement, value) {
    var options = selectElement.options;
    for (var i = 0, optionsLength = options.length; i < optionsLength; i++) {
        if (options[i].value == value) {
            selectElement.selectedIndex = i;
            return true;
        }
    }
    return false;
}

setOption(document.getElementById('my-select'), 'b');

See it!

If it returns false, then the value could not be found :)