问HTML和Javascript文本区域字数统计

EN

compareText = function (str1, str2, trimStr, lowerCaseStr, callback, separator) {
if (lowerCaseStr === true) {
    str1 = str1.toLowerCase();
    str2 = str2.toLowerCase();
}
var array1 = new Array();
var array2 = new Array();
var mistakes = {
    missed: [],
    wrongTyped: []
};
separator = separator || ' ';

array1 = str1.split(separator);
array2 = str2.split(separator);
var finalLength = array1.length;

if (array2.length > array1.length) finalLength = array2.length

for (var i = 0; i < finalLength; i++) {
    var val1 = array1[i];
    var val2 = array2[i];
    if (val1 !== val2) {
        if (typeof (val2) !== 'undefined') {
            mistakes.wrongTyped.push(val2)
        } else {
            mistakes.missed.push(val1)
        }
    }
}

if (typeof (callback) !== undefined) {
    callback(mistakes);
} else {
    return mistakes;
}