demo · v138

Hint analytics

The target_hint field tells the browser whether a prerendered page will open in _self or _blank. Without the right hint, the prerender warms the wrong browsing context and the cache is wasted. This dashboard tracks hit vs miss across three rule sets and calculates waste rate.

three rule sets

Rule A — _self hint

"target_hint": "_self"

Prerender warms same-tab context. Hits when user navigates in the same tab.

Rule B — _blank hint

"target_hint": "_blank"

Prerender warms a new-tab context. Hits when user opens in a new tab.

Rule C — no hint

"target_hint": (omitted)

Browser uses a default context. May warm the wrong one — waste possible.

simulated navigations

0 cache hits
0 cache misses (wasted prerenders)
— waste rate
Click "Run all navigations" to simulate the dataset, or click individual rows.

the speculation rules JSON

<script type="speculationrules">
{
  "prerender": [
    {
      "source": "list",
      "urls": ["/product/123"],
      "eagerness": "moderate",
      "target_hint": "_self"
    },
    {
      "source": "list",
      "urls": ["/blog/post"],
      "eagerness": "moderate",
      "target_hint": "_blank"
    }
  ]
}
</script>

<!-- Without target_hint, a prerender for /product/123 might warm
     a new-tab context, then the user clicks the link in the same
     tab — the prerender is thrown away. The hint prevents this. -->

see also