# How to check if a number evaluates to Infinity using JavaScript ?

The task is to check whether number evaluates to infinity or not with the help of JavaScript. Here are few techniques discussed.
Approach 1:

Example 1: This example uses the approach as discussed above.

 ` ` `<``html``> ` ` `  `<``head``> ` `    ``<``title``> ` `        ``Check if a Number evaluates to Infinity. ` `    `` ` ` ` ` `  `<``body` `style``=``"text-align:center;"` `      ``id``=``"body"``> ` `    ``<``h1` `style``=``"color:green;"`  `        ``id``=``"h1"``>   ` `            ``GeeksForGeeks   ` `        `` ` `    ``<``p` `id``=``"GFG_UP"` `       ``style="font-size: 15px;  ` `              ``font-weight: bold;"> ` `    `` ` `    ``<``button` `onclick``=``"GFG_Fun()"``> ` `        ``click here ` `    `` ` `    ``<``p` `id``=``"GFG_DOWN"`  `       ``style="color:green;  ` `              ``font-size: 20px;  ` `              ``font-weight: bold;"> ` `    `` ` `    ``<``script``> ` `        ``var up = document.getElementById('GFG_UP'); ` `        ``var down = document.getElementById('GFG_DOWN'); ` `        ``var n = 1 / 0; ` `        ``up.innerHTML = "Click on the button to check if"+ ` `          ``" Number evaluates to Infinity.<``br``> Number = 1/0"; ` ` `  `        ``function GFG_Fun() { ` `            ``if (n == Number.POSITIVE_INFINITY || n == Number.NEGATIVE_INFINITY) { ` `                ``down.innerHTML = "Infinity"; ` `            ``} else { ` `                ``down.innerHTML = "Not Infinity"; ` `            ``} ` `        ``} ` `    `` ` ` ` ` `  ` `

Output:

• Before clicking on the button:
• After clicking on the button:

Approach 2:

• Using Number.isFinite() method to check if the number is finite or not.

Example 2: This example uses the approach as discussed above.

 ` ` `<``html``> ` ` `  `<``head``> ` `    ``<``title``> ` `        ``Check if a Number evaluates to Infinity. ` `    `` ` ` ` ` `  `<``body` `style``=``"text-align:center;"``> ` `    ``<``h1` `style``=``"color:green;"``>   ` `            ``GeeksForGeeks   ` `        `` ` `    ``<``p` `id``=``"GFG_UP"`  `       ``style="font-size: 15px; ` `              ``font-weight: bold;"> ` `    `` ` `    ``<``button` `onclick``=``"GFG_Fun()"``> ` `        ``click here ` `    `` ` `    ``<``p` `id``=``"GFG_DOWN"`  `       ``style="color:green;  ` `              ``font-size: 20px;  ` `              ``font-weight: bold;"> ` `    `` ` `    ``<``script``> ` `        ``var up = document.getElementById('GFG_UP'); ` `        ``var down = document.getElementById('GFG_DOWN'); ` `        ``var n = 1 / 4; ` `        ``up.innerHTML = "Click on the button to check if"+ ` `          ``" Number evaluates to Infinity.<``br``> Number = 1/4"; ` ` `  `        ``function GFG_Fun() { ` `            ``if (!Number.isFinite(n)) { ` `                ``down.innerHTML = "Infinity"; ` `            ``} else { ` `                ``down.innerHTML = "Not Infinity"; ` `            ``} ` `        ``} ` `    `` ` ` ` ` `  ` `

Output:

• Before clicking on the button:
• After clicking on the button:

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