jquery css("width")与width()

css("width")返回的是字符串，..px

width()返回的是浮点数，可用于运算，所以要将控件居中时需要用width()而不能用css("width")

function setCenter(tag){
    tag.css({"margin-left":parseFloat(tag.parent().width()/2-tag.width()/2)});
    tag.css({"margin-top":parseFloat(tag.parent().height()/2-tag.height()/2)});
}
function showBigImage(obj)
{
    var bodyModal= $(".body-container>.body-modal");
    bodyModal.show();
    var bigImage=bodyModal.children(".big-image")
    ,    maxWidth=bodyModal.width()
    ,    maxHeight=bodyModal.height();
    console.log(maxWidth,maxHeight);
    console.log(bigImage.css("width"),bigImage.css("height"));
    bigImage.css({"width":"auto","height":"auto"}).attr("src",obj.src);
    console.log(bigImage.css("width"),bigImage.css("height"));
    var width=bigImage.width()
    ,    height=bigImage.height();
    if(width>maxWidth) {
        bigImage.css({"width":maxWidth,"height":"auto"});
        console.log("width",bigImage.css("width"),bigImage.css("height"));
    } else if(height>maxHeight) {
        bigImage.css({"height":maxHeight,"width":"auto"});
        console.log("height",bigImage.css("width"),bigImage.css("height"));
    }
    bigImage.show();
    setCenter(bigImage);
}