Feature/#33 wait class function (#63)

* #33 Lib cleanup. Added WAIT_CLASS and WAIT_CLASS_ALL functions

* #33 Fixed attr update

* #33 HTMLElement.WaitForClass

* #33 Updated HTMLDocument.WaitForClass

pkg/stdlib/html/click.go

@@ -0,0 +1,58 @@
+package html
+
+import (
+	"context"
+	"github.com/MontFerret/ferret/pkg/runtime/core"
+	"github.com/MontFerret/ferret/pkg/runtime/values"
+	"github.com/MontFerret/ferret/pkg/stdlib/html/driver/dynamic"
+)
+
+/*
+ * Dispatches click event on a given element
+ * @param source (Document | Element) - Event source.
+ * @param selector (String, optional) - Optional selector. Only used when a document instance is passed.
+ */
+func Click(_ context.Context, args ...core.Value) (core.Value, error) {
+	err := core.ValidateArgs(args, 1, 2)
+
+	if err != nil {
+		return values.False, err
+	}
+
+	// CLICK(el)
+	if len(args) == 1 {
+		arg1 := args[0]
+
+		err := core.ValidateType(arg1, core.HTMLElementType)
+
+		if err != nil {
+			return values.False, err
+		}
+
+		el, ok := arg1.(*dynamic.HTMLElement)
+
+		if !ok {
+			return values.False, core.Errors(core.ErrInvalidType, ErrNotDynamic)
+		}
+
+		return el.Click()
+	}
+
+	// CLICK(doc, selector)
+	arg1 := args[0]
+	selector := args[1].String()
+
+	err = core.ValidateType(arg1, core.HTMLDocumentType)
+
+	if err != nil {
+		return values.None, err
+	}
+
+	doc, ok := arg1.(*dynamic.HTMLDocument)
+
+	if !ok {
+		return values.False, core.Errors(core.ErrInvalidType, ErrNotDynamic)
+	}
+
+	return doc.ClickBySelector(values.NewString(selector))
+}