Function getWidthOrHeight

2.0.3/Css.js:384–425

(elem, name, extra)

    }

    function getWidthOrHeight(elem, name, extra) {

        // Start with offset property, which is equivalent to the border-box value
        var valueIsBorderBox = true,
            val = name === "width" ? elem.offsetWidth : elem.offsetHeight,
            styles = getStyles(elem),
            isBorderBox = jQuery.support.boxSizing && jQuery.css(elem, "boxSizing", false, styles) === "border-box";

        // some non-html elements return undefined for offsetWidth, so check for null/undefined
        // svg - https://bugzilla.mozilla.org/show_bug.cgi?id=649285
        // MathML - https://bugzilla.mozilla.org/show_bug.cgi?id=491668
        if (val <= 0 || val == null) {
            // Fall back to computed then uncomputed css if necessary
            val = curCSS(elem, name, styles);
            if (val < 0 || val == null) {
                val = elem.style[name];
            }

            // Computed unit is not pixels. Stop here and return.
            if (rnumnonpx.test(val)) {
                return val;
            }

            // we need the check for style in case a browser which returns unreliable values
            // for getComputedStyle silently falls back to the reliable elem.style
            valueIsBorderBox = isBorderBox && (jQuery.support.boxSizingReliable || val === elem.style[name]);

            // Normalize "", auto, and prepare for extra
            val = parseFloat(val) || 0;
        }

        // use the active box-sizing model to add/subtract irrelevant styles
        return (val +
            augmentWidthOrHeight(
                elem,
                name,
                extra || (isBorderBox ? "border" : "content"),
                valueIsBorderBox,
                styles
            )
        ) + "px";
    }

    // Try to determine the default display value of an element