文本框自动变长

 <input type="text" value="" class=\"queryInput\" />

var curNode = "input.queryInput";
var curWidth = $(curNode).eq(0).width();
var curMaxWidth = 700;
$(curNode).eq(0).keyup(function() {
    var curTxtWidth = $(curNode).eq(0).width();
    var node = $("#widthAuto");
    if (node.length > 0) {
        node = $("#widthAuto");
        node.html($(this).val())
    } else {
        node = $("<span id=\"widthAuto\" style=\"visibility:hidden;\">" + $(this).val() + "</span>");
        $("body").append(node)
    }
    var curAllWidth = node.width() + 149;
    if (curWidth > curAllWidth) {
        $(curNode).eq(0).css("width", curWidth)
    } else {
        if (curMaxWidth > curAllWidth) {
            $(curNode).eq(0).css("width", curAllWidth)
        }
    }
})