Correspondent ASCII characters.

to_ascii.js

/**
 * To ASCII.
 * 
 * @param {string} text
 * @returns {string}
 */
function toAscii(text) {
    var noAscii = 'áàãâäéèêëíìîïóòõôöúùûüçÁÀÃÂÄÉÈÊËÍÌÎÏÓÒÕÖÔÚÙÛÜÇ';
    var ascii = 'aaaaaeeeeiiiiooooouuuucAAAAAEEEEIIIIOOOOOUUUUC';
    var resultText = '';
    
    for (var i = 0; i < text.length; i++) {
        resultText += (noAscii.indexOf(text.charAt(i)) !== -1)
            ? ascii.substr(noAscii.search(text.substr(i, 1)), 1)
            : text.substr(i, 1);
    }
    
    return resultText;
}