Carla-de-Beer

function initShaders( gl, vertexShaderId, fragmentShaderId )
{
    var vertShdr;
    var fragShdr;

    var vertElem = document.getElementById( vertexShaderId );
    if ( !vertElem ) { 
        alert( "Unable to load vertex shader " + vertexShaderId );
        return -1;
    }

Carla-de-Beer

// Shader initialisation

function getShader(gl, id){
	var shaderScript = document.getElementById(id);
	
	if (!shaderScript) {
		return null;
	}

	var str = "";