diff --git a/VERSION b/VERSION
index f1bb104b..455f47c0 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-Version 2.4.7-stable+timestamp.2013.06.01.18.23.56
+Version 2.4.7-stable+timestamp.2013.06.03.17.47.22
diff --git a/applications/admin/static/js/web2py.js b/applications/admin/static/js/web2py.js
index f9fce21d..c4d5ee13 100644
--- a/applications/admin/static/js/web2py.js
+++ b/applications/admin/static/js/web2py.js
@@ -78,6 +78,7 @@ jQuery(function() {
    if(flash.html()) flash.append('<span id="closeflash">&times;</span>').slideDown();
    web2py_ajax_init(document);
    web2py_event_handlers();
+   web2py_show_if();
 });
 
 function web2py_trap_form(action,target) {
@@ -216,3 +217,26 @@ function web2py_validate_entropy(myfield, req_entropy) {
     if(!myfield.hasClass('entropy_check')) myfield.on('keyup', validator).on('keydown', validator).addClass('entropy_check');
 }
 
+function web2py_show_if() {
+    var triggers = {};
+    var show_if = function() {
+        var t = jQuery(this);	
+	var id = t.attr('id');
+	t.attr('value',t.val());
+	for(var k=0; k<triggers[id].length; k++) {
+            var dep = jQuery('#'+triggers[id][k]);
+            var tr = jQuery('#'+triggers[id][k]+'__row');
+	    if(t.is(dep.attr('data-show-if'))) tr.slideDown();
+            else tr.hide();
+	}
+    };
+    jQuery('[data-show-trigger]').each(function(){	
+	var name = jQuery(this).attr('data-show-trigger');
+        if(!triggers[name]) triggers[name] = [];
+	triggers[name].push(jQuery(this).attr('id'));
+    });
+    for(var name in triggers) {
+	jQuery('#'+name).change(show_if).keyup(show_if);
+        show_if.call(jQuery('#'+name));
+    };
+}
\ No newline at end of file
diff --git a/applications/examples/static/js/web2py.js b/applications/examples/static/js/web2py.js
index f9fce21d..c4d5ee13 100644
--- a/applications/examples/static/js/web2py.js
+++ b/applications/examples/static/js/web2py.js
@@ -78,6 +78,7 @@ jQuery(function() {
    if(flash.html()) flash.append('<span id="closeflash">&times;</span>').slideDown();
    web2py_ajax_init(document);
    web2py_event_handlers();
+   web2py_show_if();
 });
 
 function web2py_trap_form(action,target) {
@@ -216,3 +217,26 @@ function web2py_validate_entropy(myfield, req_entropy) {
     if(!myfield.hasClass('entropy_check')) myfield.on('keyup', validator).on('keydown', validator).addClass('entropy_check');
 }
 
+function web2py_show_if() {
+    var triggers = {};
+    var show_if = function() {
+        var t = jQuery(this);	
+	var id = t.attr('id');
+	t.attr('value',t.val());
+	for(var k=0; k<triggers[id].length; k++) {
+            var dep = jQuery('#'+triggers[id][k]);
+            var tr = jQuery('#'+triggers[id][k]+'__row');
+	    if(t.is(dep.attr('data-show-if'))) tr.slideDown();
+            else tr.hide();
+	}
+    };
+    jQuery('[data-show-trigger]').each(function(){	
+	var name = jQuery(this).attr('data-show-trigger');
+        if(!triggers[name]) triggers[name] = [];
+	triggers[name].push(jQuery(this).attr('id'));
+    });
+    for(var name in triggers) {
+	jQuery('#'+name).change(show_if).keyup(show_if);
+        show_if.call(jQuery('#'+name));
+    };
+}
\ No newline at end of file
diff --git a/applications/welcome/static/js/web2py.js b/applications/welcome/static/js/web2py.js
index f9fce21d..c4d5ee13 100644
--- a/applications/welcome/static/js/web2py.js
+++ b/applications/welcome/static/js/web2py.js
@@ -78,6 +78,7 @@ jQuery(function() {
    if(flash.html()) flash.append('<span id="closeflash">&times;</span>').slideDown();
    web2py_ajax_init(document);
    web2py_event_handlers();
+   web2py_show_if();
 });
 
 function web2py_trap_form(action,target) {
@@ -216,3 +217,26 @@ function web2py_validate_entropy(myfield, req_entropy) {
     if(!myfield.hasClass('entropy_check')) myfield.on('keyup', validator).on('keydown', validator).addClass('entropy_check');
 }
 
+function web2py_show_if() {
+    var triggers = {};
+    var show_if = function() {
+        var t = jQuery(this);	
+	var id = t.attr('id');
+	t.attr('value',t.val());
+	for(var k=0; k<triggers[id].length; k++) {
+            var dep = jQuery('#'+triggers[id][k]);
+            var tr = jQuery('#'+triggers[id][k]+'__row');
+	    if(t.is(dep.attr('data-show-if'))) tr.slideDown();
+            else tr.hide();
+	}
+    };
+    jQuery('[data-show-trigger]').each(function(){	
+	var name = jQuery(this).attr('data-show-trigger');
+        if(!triggers[name]) triggers[name] = [];
+	triggers[name].push(jQuery(this).attr('id'));
+    });
+    for(var name in triggers) {
+	jQuery('#'+name).change(show_if).keyup(show_if);
+        show_if.call(jQuery('#'+name));
+    };
+}
\ No newline at end of file
diff --git a/gluon/sqlhtml.py b/gluon/sqlhtml.py
index 59efe9c9..e14340f4 100644
--- a/gluon/sqlhtml.py
+++ b/gluon/sqlhtml.py
@@ -81,6 +81,27 @@ def safe_float(x):
         return 0
 
 
+def show_if(cond):
+    if not cond:
+        return None
+    base = "%s_%s" % (cond.first.tablename, cond.first.name)
+    if ((cond.op.__name__ == 'EQ' and cond.second == True) or 
+        (cond.op.__name__ == 'NE' and cond.second == False)):            
+        return base,":checked"
+    if ((cond.op.__name__ == 'EQ' and cond.second == False) or
+        (cond.op.__name__ == 'NE' and cond.second == True)):
+        return base,":not(:checked)"
+    if cond.op.__name__ == 'EQ':
+        return base,"[value='%s']" % cond.second
+    if cond.op.__name__ == 'NE':
+        return base,"[value!='%s']" % cond.second
+    if cond.op.__name__ == 'CONTAINS':
+        return base,"[value~='%s']" % cond.second    
+    if cond.op.__name__ == 'BELONGS' and isinstance(cond.second,(list,tuple)):
+        return base,','.join("[value='%s']" % (v) for v in cond.second)
+    raise RuntimeError("Not Implemented Error")
+
+
 class FormWidget(object):
     """
     helper for SQLFORM to generate form input fields
@@ -104,9 +125,13 @@ class FormWidget(object):
             _id='%s_%s' % (field._tablename, field.name),
             _class=cls._class or
                 widget_class.match(str(field.type)).group(),
-            _name=field.name,
+            _name=field.name,            
             requires=field.requires,
         )
+        if getattr(field,'show_if',None):
+            trigger, cond = show_if(field.show_if)
+            attr['_data-show-trigger'] = trigger
+            attr['_data-show-if'] = cond
         attr.update(widget_attributes)
         attr.update(attributes)
         return attr
@@ -1740,6 +1765,7 @@ class SQLFORM(FORM):
         return CAT(
             DIV(_id=panel_id, _style="display:none;", *criteria), fadd)
 
+
     @staticmethod
     def grid(query,
              fields=None,