JavaScript/Search/linearSearch.js

/*
 * Linear search or sequential search is a method for finding a target
 * value within a list. It sequentially checks each element of the list
 * for the target value until a match is found or until all the elements
 * have been searched.
 */
function SearchArray(searchNum, ar) {
    var position = Search(ar, searchNum);
    if (position != -1) {
        console.log("The element was found at " + (position + 1));
    } else {
        console.log("The element not found");
    }
}

// Search “theArray” for the specified “key” value
function Search(theArray, key) {
    for (var n = 0; n < theArray.length; n++)
        if (theArray[n] == key)
            return n;
    return -1;
}

var ar = [1, 2, 3, 4, 5, 6, 7, 8, 9];
SearchArray(3, ar);
SearchArray(4, ar);
SearchArray(11, ar);