diff --git a/static/js/crementing.js b/static/js/crementing.js
new file mode 100644
index 0000000..a80e600
--- /dev/null
+++ b/static/js/crementing.js
@@ -0,0 +1,12 @@
+/*
+this is thought for (de-/in)crement integer values in (e.g. input) form elements
+calling like
+  <input type="input" value="++" onclick="crmnt(document.getElementById('id'),1)" />
+  <input type="input" value="+=5" onclick="crmnt(document.getElementById('id'),5)" />
+  <input type="input" value="-=5" onclick="crmnt(document.getElementById('id'),-5)" />
+  <input type="input" value="--" onclick="crmnt(document.getElementById('id'),-1)" />
+*/
+function crmnt( e, i ) { /* read: in-/decrement ( dom-element, signed-integer ) */
+  var d = parseInt( e.value ) + i;
+  e.value = ( d < 0 )? 0 : e.value = d;
+}