How to detect my font is correctly rendered at browsers ?

[cataclysmuprising]

Has there any way to detect my font was correctly rendered at browsers ?

To clarify my question , my API server was send Unicode Myanmar texts as response and I setted them as values of input boxes (textboxes,textareas etc). But when I was changed my browser's font to ZawGyi Font , I can't see correctly the texts of my input boxes.

I can't receive the the browser's active font, so I would like to detect when the Unicode texts are not correctly displayed and I would like to convert them as ZawGyi text values.

Any suggestions would be really appreciated. Thanks

[cataclysmuprising]

Now I had solved my problem. Actually the text width of incorrect rendered text is quite different than actual. So , when the users was setted "Zawgyi-One" as their browser's standard font and my webpage shows the "Unicode" texts, the browsers rendered incorrectly.

To fix this issue , I putted some "Unicode" Myanmar texts and check the text-width of it's allocated on page. Below is code snipet how did I solved.

function getTextWidth(text, font) {
    // re-use canvas object for better performance
    var canvas = getTextWidth.canvas || (getTextWidth.canvas = document.createElement("canvas"));
    var context = canvas.getContext("2d");
    context.font = font;
    var metrics = context.measureText(text);
    return metrics.width;
}

function detectAndConvertMyanmarFont() {
    // normal width would be around 130px but if the user was changed Zawgyi font as their browser's standard font, the width value may longer
    // around 180px for text ဝိပ္ပယုတ္တပစ္စာဣန္ဒြိယသမ္ပယုတ္တ
    var fontDetectorWidth = getTextWidth("ဝိပ္ပယုတ္တပစ္စာဣန္ဒြိယသမ္ပယုတ္တ", "normal 11px 'Roboto Regular'");

    if (fontDetectorWidth > 135) {
        var converter = new google_myanmar_tools.ZawgyiConverter();
        $("input[type='text'],textarea").each(function (index, elem) {
            $(elem).val(converter.unicodeToZawgyi($(elem).val()));
        });
    }
}