jQuery selector: How can I pass value from var colorid into selector?

var obj = document.getElementById("<开发者_如何学运维;%= tbUpdate.ClientID %>");
    var colorid = obj.value;
    $('.shade[colorId=colorid]').addClass('active');

the problem is with the colorId=colorid. I think jQuery thinks that it's string. How can I pass value from var colorid into selector?

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$('.shade[colorId=' + colorid + ']');

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If you want to use the value of colorId you would need to pass a string to the jQuery selector using concatenation$('.shade[colorId=' + colorid + ']').

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$('.shade[colorId=' + colorid + ']').addClass('active');