js array check code example

Example 1: javascript check if is array

var colors=["red","green","blue"];

if(Array.isArray(colors)){
    //colors is an array
}

Example 2: js test if array

if(Array.isArray(myVarToTest)) {
	// myVatToTest is an array
} else {
	// myVarToTest is not an array
}

Example 3: js check if array

Array.isArray([1, 2, 3]);	// true
Array.isArray('asdf');		// false

Example 4: js check if is array

if(Array.isArray(colors)){
    //colors is an array
}

Example 5: javascript check if in array

var extensions = ["image/jpeg","image/png","image/gif"];          
if(extensions.indexOf("myfiletype") === -1){
	alert("Image must be .png, .jpg or .gif");
}