rangeslider.js is not accessible (https://github.com/andreruffert/rangeslider.js/issues/47), its math is wrong in getPositionFromValue, and it treats 0 as falsy.

patch.diff

diff --git a/app/assets/javascripts/rangeslider.js b/app/assets/javascripts/rangeslider.js
index 1531b77..9637194 100644
--- a/app/assets/javascripts/rangeslider.js
+++ b/app/assets/javascripts/rangeslider.js
@@ -107,7 +107,7 @@
         this.identifier = 'js-' + pluginName + '-' +(pluginIdentifier++);
         this.min        = parseFloat(this.$element[0].getAttribute('min') || 0);
         this.max        = parseFloat(this.$element[0].getAttribute('max') || 100);
-        this.value      = parseFloat(this.$element[0].value || this.min + (this.max-this.min)/2);
+        this.value      = parseFloat(this.$element[0].getAttribute('value') || this.min + (this.max - this.min) / 2);
         this.step       = parseFloat(this.$element[0].getAttribute('step') || 1);
         this.$fill      = $('<div class="' + this.options.fillClass + '" />');
         this.$handle    = $('<div class="' + this.options.handleClass + '" />');
@@ -221,7 +221,7 @@
         var value, left;
 
         // Snapping steps
-        value = (this.getValueFromPosition(this.cap(pos, 0, this.maxHandleX)) / this.step) * this.step;
+        value = this.getValueFromPosition(this.cap(pos, 0, this.maxHandleX));
         left = this.getPositionFromValue(value);
 
         // Update ui
@@ -256,16 +256,16 @@
 
     Plugin.prototype.getPositionFromValue = function(value) {
         var percentage, pos;
-        percentage = (value - this.min)/(this.max - this.min);
+        percentage = (value - this.min) / (this.max - this.min);
         pos = percentage * this.maxHandleX;
         return pos;
     };
 
     Plugin.prototype.getValueFromPosition = function(pos) {
         var percentage, value;
-        percentage = ((pos) / (this.maxHandleX || 1));
-        value = this.step * Math.ceil((((percentage) * (this.max - this.min)) + this.min) / this.step);
-        return Number((value).toFixed(2));
+        percentage = pos / (this.maxHandleX || 1);
+        value = Math.round(percentage * (this.max - this.min) / this.step) * this.step + this.min;
+        return Number(value.toFixed(2));
     };
 
     Plugin.prototype.setValue = function(value) {