Import Polymer 0.8 and several key elements.

third_party/polymer/v0_8/components-chromium/paper-input/paper-input-char-counter-extracted.js

+
+
+(function() {
+
+  Polymer({
+
+    is: 'paper-input-char-counter',
+
+    enableCustomStyleProperties: true,
+
+    hostAttributes: {
+      'add-on': ''
+    },
+
+    properties: {
+
+      /**
+       * The associated input element.
+       */
+      inputElement: {
+        type: Object
+      },
+
+      /**
+       * The current value of the input element.
+       */
+      value: {
+        type: String
+      },
+
+      /**
+       * The character counter string.
+       */
+      charCounter: {
+        computed: '_computeCharCounter(inputElement,value)',
+        type: String
+      }
+
+    },
+
+    attached: function() {
+      this.fire('addon-attached');
+    },
+
+    _computeCharCounter: function(inputElement,value) {
+      var str = value.length;
+      if (inputElement.hasAttribute('maxlength')) {
+        str += '/' + inputElement.maxLength;
+      }
+      return str;
+    }
+
+  });
+
+})();
+